Precision Innovation Complexity

Nature is the model

Integrated thread

Exact logo reproduction

Fig.1: Conventional manufacturing vs. Metal injecti on moulding

turned

turned

axially pressedCNC milled

Brushed structure from mould

Complexity & cost control

Highly complex forms in nature have often served as a basis for the design ofnew components and systems; their complete realisation can however often becompromised by the limitations of conventional production processes. OBEtherefore offers a highly innovative powder metallurgy forming process in theform of metal injection moulding (MIM) for the near net-shape manufacture ofmetal components in a wide variety of forms which e.g. would not be possiblewith machined production.The MIM process combines the advantages of the large degree of designfreedom that comes with plastic injection moulding with the excellentmechanical characteristics of metallic materials. Based on many years ofexperience in the production of precision components using machiningtechnology, OBE has advanced to become a specialist in the field of MIMtechnology since 1996 and produces high-precision metal injection mouldedcomponents for a wide variety of industries under the brand name mimplus®.

Large degree of design freedom

The injection moulding of metallic powders does not only offer designers andengineers the highest degree of design freedom but also has other advantagescompared to conventional production processes: instead of just connectingseveral parts, a functional integration can be achieved via the MIM process“from a single mould” (Fig. 1), often meaning that a reduction in weight andthus cost can be achieved whilst retaining the same level of constructionalstability.

As with the processing of plastics, many classic reworking steps such as e.g.undercuts, cross-holes, blind holes, threads, surface finishing structures or theexact reproduction of logos on the surface of the component, can be integratedin the first processing step.

The MIM process thus connects two worlds that had been completely separatefor the designer up to now: Based on plastic components, their design freedomcan now also be extended to metal components which are subject to highmechanical stress levels and in addition to this, conventionally manufacturedmetal components can now be produced more easily and thus inexpensively orcan be equipped with additional functionality.

2

3

MIM technology is always at an advantage if the time and costs for machinedproduction are high and/or if additional added or assembly processes can beomitted.The investment in an injection moulding tool (Fig. 2) must be considered aspart of the economic calculation, as the MIM procedure is a process thatinvolves tooling. As a rule of thumb, one can say that the MIM process isespecially suited for large-scale production runs; economic feasibility canhowever be guaranteed for a wide range of production run number scenariosdepending on the industry and the complexity of the component. As OBEsexperts have many years of experience in a variety of industries from luxurygoods and medical technology right up the optical and automobile industries,you can be sure that the competent evaluation of your project is safe in ourhands.

The development and manufacture of components and subassem blies

OBE offers a “full service” for its customers from development right through toseries production: Our product management team will advise you right from thefirst draft for the optimum design of the component for the MIM process andwill accompany you professionally throughout the entire project until it hasreached series production.

OBE designs your mould in our very own mould design department anddevelops an optimum mould concept, where single or multiple cavities andmanual, semi-automatic or fully-automatic handling concepts are employed,together with you based on the your final projected production run numbers.

Before the series mould is produced by OBE, sample parts can be produced inour prototype production department either via the machined manufacture ofgreen parts or by using the sample tool for very small production runs. In bothcases important information can be gathered in the planning phase which canbe useful for the subsequent series production.

You can get an overview of the variety of materials used in powder metallurgyon pages 6 and 7.

From the idea to the series component

Production of prototypes

Fig. 2: Injection moulding tool

Series parts

Large production runs

Co-development

4

Feedstock

Injection moulding

Debinding

Sintering

Fig. 3: Comparing a green part with a sintered part

The MIM process is a powder metallurgical production process that combinesthe advantages of the design flexibility of the plastic injection moulding processwith the excellent mechanical and thermal characteristics of metallic materials.It consists of four processing steps:

Feedstock productionA metal powder of the desired composition is mixed with a thermoplastic binderand a small quantity of a lubricant (e.g. paraffin) and granulated to become afeedstock. The compound increases the injection capacity of the metal powderand guarantees the shape retention of the blanks.

Injection mouldingThe feedstock is formed and demoulded in a mould using conventionalinjection moulding machines. Blanks produced like this are called “greenparts”. They are up to 20% larger than the finished product as a result of thevolume quantity of binder (Fig. 3), but still however exhibit all the typicalgeometrical characteristics of the finished component. The sprues can beremoved and directly regranulated for the next injection moulding process.

DebindingDebinding can be carried out catalytically, thermally or via water depending onthe type of feedstock. The binder is hereby removed from the component untila residual binder content of 2-3 % remains. This backbone guarantees thestability of the “brown part” for the subsequent process.

SinteringThe components are sintered at temperatures of between 1200°C und 1400°Cin the last processing step. The remaining binder content is completelyremoved in special sintering ovens in an inert gas atmosphere. The shrinkageof the component as a result of the sintering is already calculated as adimensional feature of the mould.

Components produced using the MIM process are free of residue and attaindensity values of almost 100 %. They have similar characteristics to e.g.machined components; the MIM process is environmentally-friendly and doesnot waste resources as the granulates are recycled.

The MIM process in brief

5

Maximum component size

Flat contact surface

Transitions and burrs

Constant wall thicknesses

Fig. 4: Highest precision in MIM technology

MIM technology is especially suited for small components; therefore OBE hasspecialised in the production of components with a weight of between 0.01 g toapprox. 20 g. Larger components are possible in principal – the currentmaximum size is roughly that of a walnut (approx. 50 g).

The attainable tolerances are project-specific and are calculated by our expertstogether with you.

In addition to the geometric requirements it is very important to determine thefollowing data at an early stage in the project in order to design the optimumcomponent for you :

• Place of installation of the component/subassembly• Functional requirements• Load types• Structural requirements• Hardness values• Surface finishing

It also makes sense to observe the following guidelines from a very early stagein the design of MIM components in order to avoid refinishing and extracalibration steps and thus optimise unit costs:

Contact surfaceA flat contact surface prevents the component from deforming during thesintering process.

Wall thickness distributionConstant and even wall thicknesses enable the highest degree of dimensionalaccuracy and reproducibility.

Transitions and spruesGenerally speaking rounded edges should be preferred to sharp-formed edges.Optimally located sprues mean a higher degree of stability and facilitate theinjection process of the green parts.

Design guidelines for MIM components

6

The follow

ing material table show

s a selection of OB

E‘s standard m

aterials

The details of the m

echanical properties listed in the table are typical values.

Detailed specifications and other m

aterials on request.

The m

aterial table is subject to alterations.

Trommelpoliert7Perforierung mit LaserKunststoff-Umspritzung

Galvanic gold-plating

Tumbled process

Semi-automatic polishing

Subassembly of MIM parts

Fig. 5: Surface finishing at OBE

The plus points of mimplus ®

Many MIM components are supplied without further processing as productswhich can be directly used. The additional services which go beyond thefinished MIM product are however one of OBE‘s specialities:

Surface technologyA large number of MIM components are tumbled after they have been sinteredon OBE own systems, in order e.g. to improve the surface structure for partsthat are externally visible or perhaps to remove sharp edges or possible burrs.After they have been tumbled, it is possible to create matt, calendared or high-gloss surfaces depending on the application required. OBE is able toguarantee a constantly high level of surface finishing quality due to their manyyears of experience and access to their own specialised machines.

Coating technologyComponents can be e.g. copper-plated, nickel-plated, silver-plated or gold-plated in the company’s own electro-plating shop (see Fig. 5) which has beendesigned according to the latest environmental guidelines; additional coatingoptions such as anodic oxidation, painting, PVD coating and other decorativeor functional coatings are possible for MIM components via an establishednetwork of competent partner companies.

Component assemblyMIM components can be additionally milled on CNC processing centres inorder to attain the highest possible tolerance requirements for high precisionapplications. OBE is also capable of carrying out all subsequent mechanicalprocessing steps from drilling and calibration right up to heat treatmentprocesses.Furthermore, if required, MIM components can also be assembled togetherwith purchased parts to form assemblies or even subsystems.

Competent adviceOur project management team will gladly advise you competently on allquestions having to do with the design and layout of your MIM component orsubassembly.

8

Rotationsscharnier Zeichnung

Brillenscharnier in Designerfassung

Locking element: 0.03 g

Rotational hinge elements

Design of hinge

Assembly of locking element

Fig. 6: Spectacle hinge in a designer frame

Whilst metal injection moulding is a relatively new technology, there is still alarge number of applications for a wide range of industries in which MIMcomponents fulfil functions safely and reliably, that could not be carried outwith conventionally-manufactured components. The two following examplesillustrate this clearly:

Rotational hinge: This is a novel spectacle hinge featuring a rotatingmovement (Fig. 6).

Requirements: Simple assembly of four geometrically complex componentswhilst ensuring that there is absolutely no mixing up of the individual parts.High degree of dimensional accuracy and long service life with the greatestpossible freedom of movement of the hinge. Especially high demands werealso placed on the surface finish of the components as the finished productsare high-quality designer spectacles.

Realisation: The sum of these requirements definitely required their executionas MIM components whereby the highly complex geometries were enabledusing a two-cavity mould due to the low production run numbers. Theidentification of the individual parts was enabled via embossed letters whichwere integrated as inserts in the mould.

Summary: The spectacles have successfully made their mark on the marketover a number of years with well over 100,000 pairs sold.

Locking element : This is a micro-component that enables a springmechanism to be exchanged.

Requirements: Complex geometry which is subject to heavy mechanical stressas a result of the spring mechanism of the component in operation. Highdegree of corrosion-resistance for the further processing steps and duringusage. A secure manufacturing process guaranteeing a yearly productionoutput of over 4 million units.

Realisation: In this case powder injection moulding once again proved itself tobe the ideal technology due to the geometry and production run requirements.The stainless steel 316L is processed in a thirty-two-cavity mould; theassembly of the complete component group is subsequently carried out fullyautomatically at OBE.

Summary : This component has also seen many successful years of service.

Successful applications of mimplus ®

9

Quality as a result of competence

Fig. 7: Measuring the injection moulding tool

100% surface quality control

Modern measuring devices

Since 1996

Quality from the very beginning: The dialogue with the customer and workingtogether as partners is of paramount importance for OBE, from the firstconsultation meeting right up to the successful conclusion of an order.

The company culture of a family enterprise with a tradition in precisiontechnology going back over one hundred years is the basis for the high degreeof quality consciousness. Motivated employees and the latest productionmachines and systems are perfectly integrated within a continually-evolvingmanagement system, guaranteeing a high degree of process securitythroughout the entire supply chain.

A CAQ system records and documents the data which is relevant for quality.Worker self-control, regular checking of the processes and tools used as wellas the competent monitoring of the mass produced articles therefore enablesOBE not only to maintain its high level of quality but also to continually raise itsown quality standards. This made possible as a result of the careful evaluationand analysis of the documented quality data as well as regular internal qualityaudits which also go well beyond the requirements of DIN EN ISO 9001.

Certified quality

At OBE actual production does not start until the first sample phase has beensuccessfully completed, in which e.g. the injection moulding tool is completelydimensionally recorded at the earliest possible instance (Fig. 7), in order toeliminate the causes of even the smallest of dimensional deviations. The entiresequence of the production process is documented step by step and optimised.Material and processing parameter analyses as well as the comprehensiveappraisal of the pre-series parts, integrated within a consistent approvalprocess guarantees a run up to series production that is free of problems.

During series production OBE also carries out density tests, tensile strengthinspections, cracking tests, dimensional tests, contour inspections and surfacequality checks according to the requirements. The OBE quality managementsystem is certified on a yearly basis according to the requirements laid down inDIN EN ISO 9001 via monitoring or repeat audits. Since March 2013 OBE alsocertificated according to ISO/TS 16949:2009 for the production of highprecision components in MIM process for the automotive industry.

Finally OBE has established an environmental management system and hasbeen certified according to DIN EN ISO 14001 and validated according to theEuropean regulation 1221/2009 EMAS since 1996.

ISO 9001 - ISO/TS 16949

10

Constant innovation

Exchangeable bridge

Miniature component

Fig. 8: Innovation award

Material optimisation

EPMA awards

OBE has been successfully employing MIM technology within its sectormimplus® since 1996 and is thus one of the pioneer companies who were ableto convert this innovative technology for series production. Millions ofmanufactured components for a wide variety of industries are testimony to oursuccess and continue to motivate us to retain and further extend ourtechnological advantage through permanent further development.

Material optimisation

OBE has placed a special emphasis during development on the optimisation ofselected MIM materials with regard to their surface finishing qualities. In closecooperation with well-known feedstock suppliers, recipes can be developedwhich e.g. enable the production of high-polished stainless steel MIMcomponents with a surface finish that is second to none compared toequivalents made from solid materials.

Depending on customer requirements, the specific characteristics of materialscan be adapted, such as e.g. an increased strength, optimised protectionagainst corrosion or magnetisability. In individual cases it is also possible tospecify the specific proportion of certain alloy components such as e.g. thenickel content.

Cooperation with scientific institutions

OBE has built up close relations with universities and research institutes overthe years in order to further develop MIM technology. OBE makes an importantcontribution towards furthering this relatively new technology with industrialplacements, projects, final papers, lectures, workshops and publications aswell as participating in research projects.

Awards at tradeshows or from customers

OBEs innovative initiatives with regards to MIM technology have beenrecognised with several awards – both at tradeshows and specialist symposiaas well as from customers (Fig. 8).

OBE Ohnmacht & Baumgärtner GmbH & Co. KG · Turnstr. 22 · 75228 Ispringen · GermanyTel. +49-(0)7231-802-0 · Fax +49-(0)7231-802-388

www.mimplus.de · mimplus@obe.de

01.2

015

OBE Ohnmacht & Baumgärtner GmbH & Co. KG

OBE is a worldwide specialist in the production of small metal precisionparts and components.

We have been manufacturing complex and high-precision componentsusing the innovative MIM process in our mimplus® business sector forover 10 years.

Our customers from the luxury goods, automotive, telecommunications,medical and aerospace sectors value our comprehensive and competentservice at all stages in the production process, from development supportright up to finishing and assembly of the components and subassembliesproduced via MIM technology.

In addition to the business sector mimplus®, OBE is the leadingmanufacturer of spectacle components and screws in the field of optics.

Our headquarters in Ispringen in the Northern Black Forest has aproduction shop floor area of 15,000 m². We have an additionalproduction facility in China (Shenzhen).

OBE has over 550 employees worldwide and has distribution subsidiariesin Italy and Hong Kong as well as representatives in Japan, South Korea,France and Switzerland.