Il-granit huwa tip ta’ blat igneju estratt għas-saħħa estrema tiegħu, id-densità, id-durabbiltà, u r-reżistenza għall-korrużjoni. Iżda l-granit huwa wkoll versatili ħafna – mhux biss għal kwadri u rettangoli! Fil-fatt, naħdmu b’kunfidenza ma’ komponenti tal-granit inġinerizzati f’forom, angoli, u kurvi tal-varjazzjonijiet kollha fuq bażi regolari – b’riżultati eċċellenti.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ li jista' jiġi mmaxinjat
■ preċiżament ċatt meta maqtugħ u lest
■ reżistenti għas-sadid
■ durabbli
■ dejjiema
Il-komponenti tal-granit huma wkoll faċli biex jitnaddfu. Meta toħloq disinji apposta, kun żgur li tagħżel il-granit għall-benefiċċji superjuri tiegħu.

STANDARDS / APPLIKAZZJONIJIET TA' UTILIZZ GĦOLJA
Il-granit utilizzat minn ZHHIMG għall-prodotti standard tagħna tal-pjanċi tal-wiċċ għandu kontenut għoli ta' kwarz, li jipprovdi reżistenza akbar għall-użu u l-ħsara. Il-kuluri Superjuri Iswed tagħna għandhom rati baxxi ta' assorbiment tal-ilma, u jimminimizzaw il-possibbiltà li l-kejl ta' preċiżjoni tiegħek jissadddu waqt li jitwaħħlu fuq il-pjanċi. Il-kuluri tal-granit offruti minn ZHHIMG jirriżultaw f'inqas dija, li jfisser inqas għeja għall-għajnejn għall-individwi li jużaw il-pjanċi. Għażilna t-tipi ta' granit tagħna filwaqt li kkunsidrajna l-espansjoni termali fi sforz biex inżommu dan l-aspett minimu.

CUSTOM APPLICATIONS
Meta l-applikazzjoni tiegħek teħtieġ pjanċa b'forom apposta, inserzjonijiet bil-kamin, slots jew makkinarju ieħor, tkun trid tagħżel materjal bħal Black Jinan Black. Dan il-materjal naturali joffri ebusija superjuri, tnaqqis eċċellenti tal-vibrazzjoni, u makkinabbiltà mtejba.

Huwa importanti li wieħed jinnota li l-kulur waħdu mhuwiex indikazzjoni tal-kwalitajiet fiżiċi tal-ġebla. B'mod ġenerali, il-kulur tal-granit huwa direttament relatat mal-preżenza jew l-assenza ta' minerali, li jistgħu ma jkollhom l-ebda effett fuq il-kwalitajiet li jagħmlu materjal tajjeb għall-pjanċi tal-wiċċ. Hemm graniti roża, griżi u suwed li huma eċċellenti għall-pjanċi tal-wiċċ, kif ukoll graniti suwed, griżi u roża li mhumiex adattati għal applikazzjonijiet ta' preċiżjoni. Il-karatteristiċi kritiċi tal-granit, kif għandhom x'jaqsmu mal-użu tiegħu bħala materjal għall-pjanċi tal-wiċċ, m'għandhom x'jaqsmu xejn mal-kulur, u huma kif ġej:
■ Ebusija (deflessjoni taħt tagħbija - indikata mill-Modulu tal-Elastiċità)
■ Ebusija
■ Densità
■ Reżistenza għall-użu
■ Stabbiltà
■ Porożità

Ittestjajna ħafna materjali tal-granit u qabbilna dawn il-materjali. Fl-aħħar ir-riżultat huwa li l-granit iswed ta' Jinan huwa l-aqwa materjal li qatt rajna. Il-granit iswed Indjan u l-granit tal-Afrika t'Isfel huma simili għall-Granit Iswed ta' Jinan, iżda l-proprjetajiet fiżiċi tagħhom huma inqas minn dawk tal-Granit Iswed ta' Jinan. ZHHIMG se tkompli tfittex aktar materjal tal-granit fid-dinja u tqabbel il-proprjetajiet fiżiċi tagħhom.

Biex titkellem aktar dwar il-granit li huwa tajjeb għall-proġett tiegħek, jekk jogħġbok ikkuntattjanainfo@zhhimg.com.

Manifatturi differenti jużaw standards differenti. Hemm ħafna standards fid-dinja.
L-Istandard DIN, ASME B89.3.7-2013 jew l-Ispeċifikazzjoni Federali GGG-P-463c (Pjanċi tal-Wiċċ tal-Granit) eċċ. bħala bażi għall-ispeċifikazzjonijiet tagħhom.

U nistgħu nimmanifatturaw pjanċa ta' spezzjoni ta' preċiżjoni tal-granit skont il-ħtiġijiet tiegħek. Merħba tikkuntattjana jekk trid tkun taf aktar informazzjoni dwar aktar standards.

Il-pjanità tista' titqies bħala l-punti kollha fuq il-wiċċ li jinsabu f'żewġ pjani paralleli, il-pjan bażi u l-pjan tas-saqaf. Il-kejl tad-distanza bejn il-pjani huwa l-pjanità ġenerali tal-wiċċ. Dan il-kejl tal-pjanità ġeneralment iġorr tolleranza u jista' jinkludi denominazzjoni ta' grad.

Pereżempju, it-tolleranzi tal-flatness għal tliet gradi standard huma definiti fl-ispeċifikazzjoni federali kif determinat mill-formula li ġejja:
■ Grad AA tal-Laboratorju = (40 + kwadrat djagonali/25) x .000001" (unilaterali)
■ Grad ta' Spezzjoni A = Grad ta' Laboratorju AA x 2
■ Kamra tal-Għodda Grad B = Grad tal-Laboratorju AA x 4.

Għal pjanċi tal-wiċċ ta' daqs standard, aħna niggarantixxu tolleranzi ta' ċattità li jaqbżu r-rekwiżiti ta' din l-ispeċifikazzjoni. Minbarra l-ċattità, l-ASME B89.3.7-2013 u l-Ispeċifikazzjoni Federali GGG-P-463c jindirizzaw suġġetti li jinkludu: preċiżjoni tal-kejl ripetut, proprjetajiet tal-materjal tal-graniti tal-pjanċi tal-wiċċ, finitura tal-wiċċ, post tal-punt ta' appoġġ, ebusija, metodi aċċettabbli ta' spezzjoni, installazzjoni ta' inserzjonijiet bil-kamin, eċċ.

Il-pjanċi tal-wiċċ tal-granit ZHHIMG u l-pjanċi tal-ispezzjoni tal-granit jissodisfaw jew jaqbżu r-rekwiżiti kollha stabbiliti f'din l-ispeċifikazzjoni. Fil-preżent, m'hemm l-ebda speċifikazzjoni li tiddefinixxi l-pjanċi tal-angolu tal-granit, il-paralleli, jew il-kwadri ewlenin.

U tista' ssib il-formuli għal standards oħra f'NIŻŻEL.

L-ewwelnett, huwa importanti li l-pjanċa tinżamm nadifa. It-trab abrażiv fl-arja ġeneralment ikun l-akbar sors ta’ xedd u kedd fuq pjanċa, peress li għandu t-tendenza li jidħol fil-biċċiet tax-xogħol u fl-uċuħ ta’ kuntatt tal-gages. It-tieni, għatti l-pjanċa tiegħek biex tipproteġiha mit-trab u l-ħsara. Il-ħajja tal-użu tista’ tiġi estiża billi tgħatti l-pjanċa meta ma tkunx qed tintuża, billi ddawwar il-pjanċa perjodikament sabiex żona waħda ma tirċevix użu eċċessiv, u billi tissostitwixxi l-pads tal-kuntatt tal-azzar fuq il-gaging b’pads tal-karbur. Ukoll, evita li tpoġġi ikel jew soft drinks fuq il-pjanċa. Innota li ħafna soft drinks fihom jew aċidu karboniku jew fosforiku, li jista’ jxolji l-minerali aktar rotob u jħalli ħofor żgħar fil-wiċċ.

Dan jiddependi minn kif qed tintuża l-pjanċa. Jekk possibbli, nirrakkomandaw li l-pjanċa titnaddaf fil-bidu tal-ġurnata (jew tax-xift tax-xogħol) u mill-ġdid fl-aħħar. Jekk il-pjanċa titħammeġ, partikolarment b'fluwidi żejtnija jew li jwaħħlu, probabbilment għandha titnaddaf immedjatament.

Naddaf il-pjanċa regolarment b'likwidu jew b'ZHHIMG Waterless surface plate cleaner. L-għażla tas-soluzzjonijiet tat-tindif hija importanti. Jekk jintuża solvent volatili (aċetun, irqaq tal-laker, alkoħol, eċċ.) l-evaporazzjoni se tkessaħ il-wiċċ, u tgħawweġh. F'dan il-każ, huwa meħtieġ li l-pjanċa titħalla tinnormalizza qabel ma tintuża jew inkella jseħħu żbalji fil-kejl.

L-ammont ta’ ħin meħtieġ biex il-pjanċa tinnormalizza se jvarja skont id-daqs tal-pjanċa, u l-ammont ta’ tkessiħ. Siegħa għandha tkun biżżejjed għal pjanċi iżgħar. Jistgħu jkunu meħtieġa sagħtejn għal pjanċi akbar. Jekk jintuża prodott tat-tindif ibbażat fuq l-ilma, ikun hemm ukoll xi tkessiħ evaporattiv.

Il-pjanċa żżomm ukoll l-ilma, u dan jista' jikkawża s-sadid tal-partijiet tal-metall li jkunu f'kuntatt mal-wiċċ. Xi prodotti tat-tindif iħallu wkoll residwu li jwaħħal wara li jinxef, li jattira t-trab fl-arja, u fil-fatt iżid l-użu, minflok ma jnaqqas.

Dan jiddependi fuq l-użu tal-pjanċa u l-ambjent. Nirrakkomandaw li pjanċa ġdida jew aċċessorju tal-granit ta' preċiżjoni jirċievu kalibrazzjoni mill-ġdid sħiħa fi żmien sena mix-xiri. Jekk il-pjanċa tal-wiċċ tal-granit se tara użu qawwi, jista' jkun rakkomandabbli li dan l-intervall jitqassar għal sitt xhur. Spezzjoni ta' kull xahar għal żbalji fil-kejl ripetuti bl-użu ta' livell elettroniku, jew apparat simili se turi kwalunkwe tikek ta' xedd li qed jiżviluppaw u tieħu biss ftit minuti biex titwettaq. Wara li jiġu determinati r-riżultati tal-ewwel kalibrazzjoni mill-ġdid, l-intervall tal-kalibrazzjoni jista' jiġi estiż jew imqassar kif permess jew meħtieġ mis-sistema ta' kwalità interna tiegħek.

Nistgħu noffru servizz biex ngħinuk tispezzjona u tikkalibra l-pjanċa tal-wiċċ tal-granit tiegħek.

Hemm diversi kawżi possibbli għal varjazzjonijiet bejn il-kalibrazzjonijiet:

• Il-wiċċ inħasel b'soluzzjoni sħuna jew kiesħa qabel il-kalibrazzjoni, u ma ngħatax biżżejjed ħin biex jiġi normalizzat
• Il-pjanċa mhix appoġġjata kif suppost
• Bidla fit-temperatura
• Abbozzi
• Dawl tax-xemx dirett jew sħana radjanti oħra fuq il-wiċċ tal-pjanċa. Kun żgur li d-dawl minn fuq ma jkunx qed isaħħan il-wiċċ.
• Varjazzjonijiet fil-gradjent tat-temperatura vertikali bejn ix-xitwa u s-sajf (Jekk possibbli, kun af it-temperatura tal-gradjent vertikali fil-ħin li titwettaq il-kalibrazzjoni.)
• Il-pjanċa ma ngħatatx ​​biżżejjed ħin biex tinnormalizza wara l-ġarr
• Użu mhux xieraq ta' tagħmir ta' spezzjoni jew użu ta' tagħmir mhux kalibrat
• Bidla fil-wiċċ li tirriżulta mill-użu

Kemm hemm tipi ta' toqob fuq granit ta' preċiżjoni?

Slots fuq Komponenti tal-Granit ta' Preċiżjoni

Għal ħafna fabbriki, kmamar ta' spezzjoni u laboratorji, pjanċi tal-wiċċ tal-granit ta' preċiżjoni huma dipendenti fuqhom bħala l-bażi għal kejl preċiż. Minħabba li kull kejl lineari jiddependi fuq wiċċ ta' referenza preċiż li minnu jittieħdu d-dimensjonijiet finali, il-pjanċi tal-wiċċ jipprovdu l-aħjar pjan ta' referenza għall-ispezzjoni tax-xogħol u t-tqassim qabel il-magni. Huma wkoll bażijiet ideali biex isiru kejl tal-għoli u kejl tal-uċuħ. Barra minn hekk, grad għoli ta' ċatt, stabbiltà, kwalità ġenerali u abbilità jagħmluhom għażla tajba għall-immuntar ta' sistemi sofistikati ta' kejl mekkaniku, elettroniku u ottiku. Għal kwalunkwe minn dawn il-proċessi ta' kejl, huwa imperattiv li l-pjanċi tal-wiċċ jinżammu kalibrati.

Repeat Measurements and Flatness

Kemm il-pjanità kif ukoll il-kejl ripetut huma kritiċi biex jiżguraw wiċċ ta' preċiżjoni. Il-pjanità tista' titqies bħala l-punti kollha fuq il-wiċċ li jinsabu f'żewġ pjani paralleli, il-pjan bażi u l-pjan tas-saqaf. Il-kejl tad-distanza bejn il-pjani huwa l-pjanità ġenerali tal-wiċċ. Dan il-kejl tal-pjanità ġeneralment iġorr tolleranza u jista' jinkludi denominazzjoni ta' grad.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

Standard DIN, Standard GB, Standard ASME, standard JJS... pajjiż differenti bi stand differenti...

Aktar dettalji dwar l-istandard.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Biex jiġi żgurat li pjanċa tal-wiċċ tissodisfa kemm l-ispeċifikazzjonijiet tal-flatness kif ukoll dawk tal-kejl ripetut, il-manifatturi tal-pjanċi tal-wiċċ tal-granit għandhom jużaw l-Ispeċifikazzjoni Federali GGG-P-463c bħala bażi għall-ispeċifikazzjonijiet tagħhom. Dan l-istandard jindirizza l-eżattezza tal-kejl ripetut, il-proprjetajiet tal-materjal tal-granit tal-pjanċa tal-wiċċ, il-finitura tal-wiċċ, il-post tal-punt ta' appoġġ, l-ebusija, metodi aċċettabbli ta' spezzjoni u installazzjoni ta' inserzjonijiet bil-kamin.

Checking Plate Accuracy

Billi ssegwi ftit linji gwida sempliċi, investiment fi pjanċa tal-wiċċ tal-granit għandu jdum għal ħafna snin. Skont l-użu tal-pjanċa, l-ambjent tal-ħanut tax-xogħol u l-eżattezza meħtieġa, il-frekwenza tal-iċċekkjar tal-eżattezza tal-pjanċa tal-wiċċ tvarja. Regola ġenerali hija li pjanċa ġdida tirċievi kalibrazzjoni mill-ġdid sħiħa fi żmien sena mix-xiri. Jekk il-pjanċa tintuża ta' spiss, huwa rakkomandabbli li dan l-intervall jitqassar għal sitt xhur.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

F'xi każijiet, ikun hemm varjazzjonijiet bejn il-kalibrazzjonijiet tal-pjanċi tal-wiċċ. Kultant fatturi bħal bidla fil-wiċċ li tirriżulta minn xedd u kedd, użu mhux korrett ta' tagħmir ta' spezzjoni jew użu ta' tagħmir mhux kalibrat jistgħu jispjegaw dawn il-varjazzjonijiet. Madankollu, iż-żewġ fatturi l-aktar komuni huma t-temperatura u l-appoġġ.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Jekk issegwi ftit linji gwida, tnaqqas il-kedd fuq pjanċa tal-wiċċ tal-granit u fl-aħħar mill-aħħar, testendi l-ħajja tagħha.

L-ewwel, huwa importanti li l-pjanċa tinżamm nadifa. It-trab li jobrox fl-arja ġeneralment ikun l-akbar sors ta' xedd u kedd fuq pjanċa, peress li għandu t-tendenza li jidħol fil-biċċiet tax-xogħol u fl-uċuħ ta' kuntatt tal-gauges.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Dawwar il-pjanċa perjodikament sabiex żona waħda ma tirċevix użu eċċessiv. Barra minn hekk, huwa rakkomandat li l-pads tal-kuntatt tal-azzar fuq il-kejl jiġu sostitwiti b'pads tal-karbur.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Meta pjanċa tal-wiċċ tal-granit teħtieġ wiċċ ġdid, ikkunsidra jekk dan is-servizz għandux isir fuq il-post jew fil-faċilità tal-kalibrazzjoni. Dejjem huwa preferibbli li l-pjanċa terġa' tiġi rfinuta fil-fabbrika jew f'faċilità ddedikata. Madankollu, jekk il-pjanċa ma tkunx milbusa wisq, ġeneralment fi żmien 0.001 pulzier mit-tolleranza meħtieġa, tista' tiġi rfinuta fuq il-post. Jekk pjanċa tkun milbusa sal-punt fejn tkun aktar minn 0.001 pulzier barra mit-tolleranza, jew jekk tkun imħaffra jew imqattgħa sew, allura għandha tintbagħat lill-fabbrika għat-tħin qabel ma terġa' tiġi rfinuta.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Għandha tingħata attenzjoni kbira fl-għażla ta' tekniku tal-kalibrazzjoni u l-irfinar mill-ġdid fuq il-post. Itlob akkreditazzjoni u vverifika li t-tagħmir li se juża t-tekniku għandu kalibrazzjoni traċċabbli. L-esperjenza hija wkoll fattur importanti, peress li tieħu ħafna snin biex titgħallem kif tirrombla l-granit ta' preċiżjoni b'mod korrett.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Il-wiċċ inħasel b'soluzzjoni sħuna jew kiesħa qabel il-kalibrazzjoni u ma ngħatax biżżejjed ħin biex jiġi normalizzat.

2. Il-pjanċa mhix appoġġjata kif suppost.

3. Bidla fit-temperatura.

4. Abbozzi.

5. Dawl tax-xemx dirett jew sħana radjanti oħra fuq il-wiċċ tal-pjanċa. Kun żgur li d-dawl minn fuq ma jkunx qed isaħħan il-wiċċ.

6. Varjazzjonijiet fil-gradjent tat-temperatura vertikali bejn ix-xitwa u s-sajf. Jekk possibbli, kun af it-temperatura tal-gradjent vertikali fil-ħin li titwettaq il-kalibrazzjoni.

7. Il-pjanċa ma ngħatatx ​​biżżejjed ħin biex tiġi normalizzata wara l-ġarr.

8. Użu mhux xieraq ta' tagħmir ta' spezzjoni jew użu ta' tagħmir mhux kalibrat.

9. Bidla fil-wiċċ li tirriżulta mill-użu.

Tech Tips

• Minħabba li kull kejl lineari jiddependi fuq wiċċ ta' referenza preċiż li minnu jittieħdu d-dimensjonijiet finali, il-pjanċi tal-wiċċ jipprovdu l-aħjar pjan ta' referenza għall-ispezzjoni tax-xogħol u t-tqassim qabel il-magni.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Programm ta' spezzjoni effettiv għandu jinkludi kontrolli regolari b'awtokollimatur, li jipprovdi kalibrazzjoni attwali tal-pjanura ġenerali traċċabbli għall-Awtorità Nazzjonali tal-Ispezzjoni.

Fost il-partiċelli minerali li jiffurmaw il-granit, aktar minn 90% huma feldspar u kwarz, li minnhom il-feldspar huwa l-aktar. Il-feldspar ħafna drabi jkun abjad, griż, u aħmar ċar, u l-kwarz ikun l-aktar bla kulur jew abjad griż, li jikkostitwixxu l-kulur bażiku tal-granit. Il-feldspar u l-kwarz huma minerali iebsin, u huwa diffiċli li jiċċaqalqu b'sikkina tal-azzar. Fir-rigward tat-tikek skuri fil-granit, prinċipalment majka sewda, hemm xi minerali oħra. Għalkemm il-bijotita hija relattivament ratba, il-kapaċità tagħha li tirreżisti l-istress mhijiex dgħajfa, u fl-istess ħin għandhom ammont żgħir fil-granit, ħafna drabi inqas minn 10%. Din hija l-kundizzjoni materjali li fiha l-granit huwa partikolarment b'saħħtu.

Raġuni oħra għaliex il-granit huwa b'saħħtu hija li l-partiċelli minerali tiegħu huma marbuta sew ma' xulxin u huma mdaħħla f'xulxin. Il-pori spiss jammontaw għal inqas minn 1% tal-volum totali tal-blat. Dan jagħti lill-granit il-ħila li jiflaħ pressjonijiet qawwija u ma jiġix ippenetrat faċilment mill-umdità.

Il-komponenti tal-granit huma magħmula minn ġebel mingħajr reżistenza għas-sadid, l-aċidu u l-alkali, reżistenza tajba għall-użu u ħajja twila ta' servizz, mingħajr manutenzjoni speċjali. Il-komponenti ta' preċiżjoni tal-granit jintużaw l-aktar fl-għodda tal-industrija tal-makkinarju. Għalhekk, jissejħu komponenti ta' preċiżjoni tal-granit jew komponenti tal-granit. Il-karatteristiċi tal-komponenti ta' preċiżjoni tal-granit huma bażikament l-istess bħal dawk tal-pjattaformi tal-granit. Introduzzjoni għall-għodda u l-kejl tal-komponenti ta' preċiżjoni tal-granit: Il-magni ta' preċiżjoni u t-teknoloġija tal-mikromagni huma direzzjonijiet ta' żvilupp importanti tal-industrija tal-manifattura tal-makkinarju, u saru indikatur importanti biex jitkejjel livell ta' teknoloġija għolja. L-iżvilupp ta' teknoloġija avvanzata u l-industrija tad-difiża huwa inseparabbli mill-magni ta' preċiżjoni u t-teknoloġija tal-mikromagni. Il-komponenti tal-granit jistgħu jiżżerżqu bla xkiel fil-kejl, mingħajr staġnar. Kejl tal-wiċċ tax-xogħol, grif ġenerali ma jaffettwax l-eżattezza tal-kejl. Il-komponenti tal-granit jeħtieġ li jiġu ddisinjati u prodotti skont ir-rekwiżiti tan-naħa tad-domanda.

Qasam tal-applikazzjoni:

Kif nafu lkoll, aktar u aktar magni u tagħmir qed jagħżlu komponenti tal-granit ta' preċiżjoni.

Komponenti tal-granit jintużaw għal moviment dinamiku, muturi lineari, cmm, cnc, magna tal-lejżer...

merħba tikkuntattjana għal aktar informazzjoni.

L-apparati tal-kejl tal-granit u l-komponenti mekkaniċi tal-granit huma magħmula minn granit Iswed Jinan ta’ kwalità għolja. Minħabba l-preċiżjoni għolja, id-durata twila, l-istabbiltà tajba u r-reżistenza għall-korrużjoni tagħhom, qed jintużaw dejjem aktar fl-ispezzjoni tal-prodotti tal-industrija moderna u f’oqsma xjentifiċi bħall-ispazju aerospazjali mekkaniku u r-riċerka xjentifika.

Vantaġġi

---- Darbtejn aktar iebes mill-ħadid fondut;

---- Bidliet minimi fid-dimensjoni huma dovuti għal bidliet fit-temperatura;

---- Ħieles mit-tgħasir, għalhekk ma jkunx hemm interruzzjoni tax-xogħol;

---- Ħieles minn burrs jew protrużjonijiet minħabba l-istruttura tal-qamħ fin u l-kolliċità insinifikanti, li tiżgura l-grad għoli ta' ċatt fuq ħajja twila ta' servizz u ma tikkawża l-ebda ħsara lil partijiet jew strumenti oħra;

----Tħaddim mingħajr problemi għall-użu ma' materjali manjetiċi;

---- Ħajja twila u ħielsa mis-sadid, li tirriżulta fi spejjeż baxxi ta' manutenzjoni.

Il-pjanċi tal-wiċċ tal-granit ta' preċiżjoni huma mdaħħla bi preċiżjoni għal standard għoli ta' ċattità biex tinkiseb preċiżjoni u jintużaw bħala bażi għall-immuntar ta' sistemi sofistikati ta' kejl mekkaniku, elettroniku u ottiku.

Xi wħud mill-karatteristiċi uniċi tal-pjanċa tal-wiċċ tal-granit:

Uniformità fl-Ebusija;

Preċiż taħt Kundizzjonijiet ta' tagħbija;

Assorbenti tal-Vibrazzjoni;

Faċli biex Tnaddaf;

Reżistenti għall-Wrap;

Porożità Baxxa;

Mhux abrażiv;

Mhux Manjetiku

Vantaġġi tal-Pjanċa tal-Wiċċ tal-Granit

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.