Lock

Terms of delivery:

1. Definition and scope

1.1Investmentcasting is a process by which a high surface quality can bemanufacturedthrough the formation of dimensionally accurate casting.The patternsproduced by injection
moulding are heat disposable andare melted outafter manufacture of the ceramic moulds. The ceramicmoulds aredestroyed after casting. For this reason, both the patternand themoulds are designated lost using this method. Casting usuallytakesplace into hot moulds.

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

1.3Thistechnical memorandum does not apply precious metals cast usingthedewaxing method, to products of the jewellery industry,dentallaboratories or to art casting.

2. Purpose

2.1Thistechnical memorandum defines dimensional tolerances, specifiesmachiningallowances and surface roughness corresponding to the startof the artin the field of investment casting. It serves as a basis foroptimumeconomic cooperation between investment casting suppliers andbuyers.

2.2The specifications mentioned hererefer to sandblasted preserved orpickled surfaces in their deliveredcondition. Exception must be agreedwhere work processes are involved
which alter the dimensional tolerances.

2.3Unlessotherwise agreed, initial samples are supplied for first-timeorders.These are used to permit concrete mutual agreement betweensupplier andpurchaser. Initial samples must be appraised by the buyer,followed by awritten release to the foundry for series production.Deviationacknowledged by the release or with positive appraisal of theinitialsamples are binding for the production process and must beentered intothe (casting) drawing.

3. Dimensional accuracy

3.1 Contraction and shrinkage
Duringthesolidification and cooling of cast metals, a contraction of thevolumenaturally occurs as a result of shrinkage. Other factorsinfluencing theproduction of instrument
castings can result fromthe shrinkage ofthe lost pattern and the expansion of moulds duringheating. The sum ofthese influencing factors is taken intoconsideration in the shrinkage
allowanceduring the manufacture ofinjection moulds. The shrinkage allowance isbased on experiencevalues, depending on the contour of the casting, theceramic shell andthe casting materials, as well as the castingtechniques used in theindividual foundries.

3.2 Reference planes and reference points
Drawingusedin the manufacture of casting must be gauged systematicallyusingreference or locating points in order to ensure that dimensionalchecksand subsequent machining are in agreement. Reference points mustbedetermined right from the early design stage and  coordinatedbetweenthe zero position of the reference planes is precisely definedby meansof the reference point dimensions. All reference points mustbearranged in such a way that they are not removed or altered duringthesubsequent machining process. Reference points should be positionedonthe outside surfaces of the investment casting. They may take theformof raised or reference points are beneficial when dealing withcastingswith restricted shape and position tolerances. When determiningthereference points, attention should be paid to
ensuring that theydonot fall in the area of a sprue. In case of complex shaping, itispossible in this way to position the casting precisely by(pre-)machining the locating points.

3.3 Overdefinition
According to DIN 406, overdefinition 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.Exceptionsto this for reason of mouldmaking or casting necessity mustbe agreedbetween the investment 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
Theachievableaccuracy level of the rated dimensions of an investmentcasting dependson the greatest dimension and the shape of the casting.If the rateddimension (GTA) exceeds the rated dimension rangeindicated for acertain accuracy level, the overall tolerance of thecasting must betoleranced at the accuracy level (greatest tolerancefield). Deviationoutside the accuracy level must be agreed between thesupplier and thebuyer.

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

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 dimensionalaccuracy 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 ischaracterized by

Summary

Generallyspeaking,the investmentcasting technique is used for small pieceweights ofbetween 1 g and 10 kg. Larger work-pieces up to 150 kg arealso possible.

Piece weights

Thecastingare produced without anytrace of flash, and with an excellentsurfacefinish. In many cases-expect for producingthe required seatdimensionsthere is no need for a follow-on machiningprocess.

Surface quality

Allcastablematerials can beprocessed using this method. Investmentcasting isparticularly suitable foruse with materials unsuited tomachining.

Material selection

Full service manufacturing of investment castings, includingmachining,heat treating, passivation, plating, polishing,and painting, assembling.

We offer stainless steel casting carbon or alloy steel by investment casting in accordancewith customers design(OEM).

Lock parts

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