Lock

Terms of delivery:

1. Definition and scope

1.1Investmentcastingisaprocess by which a high surface quality can bemanufacturedthroughtheformation of dimensionally accurate casting.Thepatternsproducedbyinjection
moulding are heat disposable and aremeltedoutaftermanufacture of the ceramic moulds. The ceramicmouldsaredestroyed aftercasting. For this reason, both the patternandthemoulds are designatedlost using this method. Castingusuallytakesplace into hot moulds.

1.2 Metals and nickel-based alloys can be used for investment casting.

1.3Thistechnicalmemorandumdoesnot apply precious metals cast using thedewaxingmethod,to productsofthe jewellery industry,dentallaboratories or toart casting.

2. Purpose

2.1Thistechnicalmemorandumdefinesdimensional tolerances, specifies machiningallowancesandsurfaceroughness corresponding to the startof the art inthe fieldofinvestmentcasting. It serves as a basis for optimumeconomiccooperationbetweeninvestment casting suppliers and buyers.

2.2Thespecificationsmentionedherereferto sandblasted preserved or pickledsurfaces in theirdeliveredcondition.Exception must be agreedwherework processes areinvolved
which alter the dimensional tolerances.

2.3Unlessotherwiseagreed,initialsamples are supplied for first-timeorders.These are usedtopermitconcrete mutual agreement betweensupplier andpurchaser.Initialsamplesmust be appraised by thebuyer,followed by awritten release tothefoundry for seriesproduction.Deviationacknowledged bythe releaseor withpositiveappraisal of theinitialsamples are binding for theproductionprocessand must beentered intothe(casting) drawing.

3. Dimensional accuracy

3.1 Contraction and shrinkage
Duringthesolidificationandcooling of cast metals, a contraction ofthevolumenaturally occurs asaresult of shrinkage. Otherfactorsinfluencing the production ofinstrument
castingscan resultfromtheshrinkage of the lost patternand the expansion ofmouldsduringheating. The sum of these influencingfactors istakenintoconsideration in the shrinkage
allowance duringthemanufactureofinjection moulds. The shrinkage allowance isbasedonexperiencevalues,depending on the contour of the casting, theceramicshell andthe castingmaterials, as well as the casting techniquesusedin theindividualfoundries.

3.2 Reference planes and reference points
Drawingusedinthemanufacture of casting must be gauged systematicallyusingreferenceorlocating points in order to ensure that dimensionalchecksandsubsequentmachining are in agreement. Reference points mustbedeterminedright fromthe early design stage and coordinatedbetweenthezero positionof thereference planes is precisely defined bymeans ofthe referencepointdimensions. All reference points must bearranged insuch a way thattheyare not removed or altered during thesubsequentmachiningprocess.Reference points should be positioned onthe outsidesurfaces oftheinvestment casting.They may take the form ofraised orreferencepointsare beneficial when dealing with castingswithrestricted shapeandposition tolerances. When determining thereferencepoints,attentionshould be paid to ensuring that they do notfall inthe area ofasprue. In case of complex shaping,it is possible inthisway topositionthe casting precisely by(pre-)machining thelocatingpoints.

3.3 Over definition
According to DIN 406, overde finition must be avoided. Wall thicknesses must always be specified.

3.4 Mould and draught angles
Mould and draught angles are not necessary as a general
rule.Exceptionstothisforreason of mould making or casting necessity must beagreedbetweentheinvestment casting supplier and the buyer.

4. Dimensional tolerances

4.1 Linear dimensional tolerances
Achievable dimensional tolerances on investment casting are dependent on the following factors:
Casting material
Dimensions and shape of the casting
Validity of the accuracy grade

4.1.2. Dimensions and shape of the casting
Theachievableaccuracylevelof the rated dimensions of an investmentcasting dependson thegreatestdimension and the shape of thecasting.If therateddimension(GTA)exceeds the rated dimension rangeindicated foracertainaccuracy level,the overall tolerance of thecasting must betolerancedat the accuracylevel (greatest tolerancefield). Deviationoutside theaccuracy levelmust be agreed between thesupplier andthebuyer.

Note: The technical infomation above are incomplete. Please contact us for more details.

Our Precision Investment Casting Technology has been applied in theproduction of:

A high standard of surface quality

Low material allowance on surfacesto be machined

Facility for complex shaped innercontours due to the use of ceramic cores

A high degree of dimensional accuracy due to elimination of the mould parting line usually responsible forcasting imprecision

Hardly any restrictions in terms ofmaterials

Almost unlimited scope for theshaping of castings

The investment casting technique is characterized by

Summary

Generallyspeaking,theinvestmentcastingtechnique is used for small pieceweights ofbetween 1gand 10 kg.Largerwork-pieces up to 150 kg are alsopossible.

Piece weights

Thecastingareproducedwithout any trace of flash, and with anexcellentsurfacefinish.In manycases-expect for producing the requiredseatdimensionsthere isno needfor a follow-on machining process.

Surface quality

Allcastable materials canbe processed using this method. Investmentcastingisparticularly suitableforuse with materials unsuited tomachining.

Material selection

Fullservice manufacturing of investment castings, including machining,heattreating, passivation, plating, polishing,and painting.

We offer stainless steel, carbon steel or alloy steel casting made by investment casting according to customer's design.

Lock parts

Lock made by investment casting according to customer's design.