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Cost-effective solutions for metal or ceramic parts

Powder injection moulding

Focus

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The need for highly resilient and precise components is growing in virtually all industrial sectors. With the injection moulding of powdered materials (PIM) you have access to a technology that offers new design options for highly complex components made from metal (MIM) or ceramics (CIM). Consistently high-quality parts with details down to the micrometer range can be produced in high volumes.The great advantage: freedom of shape. Like no other process, powder injection moulding enables near-final-contour part production, including internal threads, difficult undercuts, gearings and free-form surfaces. PIM parts dis-play mechanical and material properties which are comparable to those of con-ventional metal and ceramic parts. Tech-nology of the future with high added value so why not benefit?

Green compact

Brown compact

Expert consulting throughout the entire process chain

Feedstock

DebindingFeedstock preparation

Injection moulding Sintering

Finished part

ReworkingBreaking sprues

Unique ARBURG service range

Binder

Powder

Example: burner for HID bulbs. Ceramic injection moulding enables the efficient production of smaller parts with equal performance.

At a glance

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Exploiting injection moulding potentialPIM technology enables the production of complex parts in high unit volumes. The production process can be highly auto-mated, production can be quickly converted to other products. ARBURG injection moulding technology is equally flexible: with the modular range of hydraulic and

electric ALLROUNDERs with application-specific equipment

versions, e.g. for multi-component technology

with the appropriate PIM-specific adapta-tion of the injection units in terms of geo-metry and wear resistance

As a result and through close co-operation with the leading material, mould and fur-nace technology manufacturers, ARBURG develops optimum, customised, user-spe-cific solutions.

Reliably achieving qualityWith the freely-programmable SELOGICA control system on each ALLOUNDER, PIM processing can be implemented for maxi-mum quality long-term. This is ensured, not only thanks to the position-regulated screw, but also to the fully integrated robotic tech-nology for gentle handling of the fragile moulded parts, the so-called green com-pacts. Functions such as compression in-jection moulding and evacuation also en-sure a high level of process stability and re-peat accuracy. The graphic symbols as well as the direct plausibility checking during sequence pro-gramming permit a good overview, and en-sure simple setup of even complex produc-tion processes. Moreover, numerous options are available for optimising, monitoring and documenting production processes.

Reliance on comprehensive supportARBURG is also a pioneer on the market for powder processing. Customers can rely on the corresponding comprehensive consult-ing, technology and service offerings throughout the process chain This is en-sured by a cross-departmental team of PIM specialists who have already set up several hundred systems world-wide.The support offerings range from material selection and preparation, moulded part-compatible design, individual machine and mould configuration, through to the debinding and sintering process. Whether for process optimisation, material or mould testing: At ARBURGs in-house powder lab-oratory, customer-specific tests can be per-formed and sample parts produced. In-depth training courses complete the unique range of services.

Example: laptop catches. Through the use of metal injection moulding, highly resilient components can be produced in any shape

for high-volume production.

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Machining technology? Stamping technology? Your product ideas can no longer be implemented cost-effectively in high unit volumes using conventional production methods. It therefore makes sense to take a closer look at powder injection moulding. With this alterna-tive method, you have almost unlimited design freedom with regard to your components, generate virtually no waste and achieve a high degree of sur-face quality as well as dimensional sta-bility. Time and cost-intensive rework-ing of parts is dispensed with. Your production becomes highly economical and efficient through the comprehen-sive linkage of all process steps. You thus produce your PIM parts just as you always expect to: reliably, flawlessly and smoothly.

Feedstock preparation: mixing powder with binderIn principle, all fine-grained, sinterable pow-ders can be mixed with a suitable polymer-based binder and then processed on injec-tion moulding machines. During mixing, the binder and powder are mixed to a homoge-neous compound, the feedstock. The selec-tion of powder materials is extensive: In ad-dition to the oxide ceramics and steels, hard and precious metals as well as cermets can also be used. Material manufacturers supply a steadily growing selection of injectable feedstocks for metals and ceramics, includ-ing magnetic versions, for example. Further-more, customer-specific feedstocks can also be developed and produced.

Injection moulding: moulded part manufactureFor the injection moulding of powder mate-rials, similar mould and process technology is used as that for plastics processing. The binder content of the feedstock is melted in the plasticising unit through heat before be-ing injected into the mould at high pres-sure. Robotic systems are generally used to remove the hardened moulded part, the so-called green compact, from the mould without damage.Material and mould changes can be per-formed in a short time. Just in time pro-duction can be easily implemented, as can unmanned volume production using the ap-propriate automation solutions.

Multi-stage: the manufacturing process

Perfect preparation: powder properties decisive

for process and component.

Precise contours: injection moulding key to subse-

quent part quality.

Extremely precise: meeting the strictest tolerances

with powder injection moulding.

0.05

0.06

0.075

0.15

0.25

0.5%

Nominal dim. mm Tolerance +/- mm+/-

60

of nominal dimension

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In order to demonstrate the complete powder processing procedure to inter-ested parties in practice, ARBURG has a unique PIM laboratory.

Here, all the steps from feedstock mixture, preparation and injection moulding through to debinding and sintering of the moulded parts can be carried out under laboratory conditions. In-depth consulting by experi-enced specialists is also available on suita-ble powder/binder mixtures, for example, on green compact production, on downstream processes, as well as on machine and mould design. A variety of test parts can be injec-tion moulded on in-house moulds.

ARBURG also develops and tests feedstock mixtures for customers. In order to optimise the feed characteristics, the feedstock can be processed into a homogeneous granulate.Finally, the PIM laboratory is equipped with the necessary facilities in order to perform all the debinding processes currently availa-ble on the market.

PIM laboratory

Debinding: removing polymerDuring debinding, the polymer component is removed from the green compact using either a catalytic process, dissolving (e.g. with water or acetone), or thermal decomposition. This process can be effec-tively supported by suitable process control measures. When the binder is removed, the moulded part becomes what is known as a brown compact. In this condition, the parts are po-rous, fragile and relatively unstable. The debinding system must be adapted to the specific binder system employed.

Sintering: mechanically stable bondingIn order to securely bond the particles of the brown compact, the part is sintered by further heating. For this purpose, a certain

furnace atmosphere and tem-perature-time profile must be maintained. The final moulded part, which

becomes denser by 15 to 25%, is produced by diffusion

and/or the formation of liquid phases and grain growth. Injection moulded,

sintered parts are characterised by great homogeneity and high material density. Fine powders and suitable mould technol-ogy ensure outstanding surface qualities and minimal tolerances.

High-quality sintering: moulded parts shrink iso-

tropically, i.e. equally in all directions.

Individually debinded: in suitable atmosphere,

dependent on binder and moulded part.

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The injection moulding of ceramic or metal powders does not differ sig-nificantly from the processing of filled plastics. This especially applies to con-sistently high quality during volume production. Faults in the moulded part such as cracks, for example, can no longer be remedied during subsequent debinding and sintering. We consequently place great value on reproducible, flawless injection mould-ing production. Only then can you as a PIM producer be on the safe side and smooth-running production be ensured.

Basis: repeat accuracyThanks to three-platen technology, clamping units with four tie-bar guidance and central force application, as well as servo-regulated mould movements, the clamping units en-sure precise moulding, protection of the mould and precise positioning. The high-pre-cision technology effectively counteracts burring. Depending on the requirements, hy-draulic or electric machine options can be used. Reproducible mould filling and particu-larly high moulded part quality are achieved by means of the uniqu