Menu

News


Vacant Position: Project and sales engineer, Valparaiso, Indiana
For our subsidiary in Valparaiso Indiana, we are looking for a project and sales engineer who...


New seminars in February 2018 in Valparaiso, Indiana
In February, we offer the following seminars at our location in Valparaiso, Indiana: ...

Development of suppliers for bearings, gearboxes and others

Bearing suppliers

Ball and roller bearings
Ball and roller bearings

Bearings produced in various economic regions are traded all over the world.Between different manufacturers, there are enormous price differences because of which approval and development of new supplies might lead to significant cost reduction. Apart from that, international operating companies might want to take advantage of local suppliers in order to avoid currency risks as well as costs for customs and shipment. Since outer dimensions of bearings are defined by standards, suppliers can easily be exchanged as long as sufficent quality is ensured.

Prior to any supplier evaluation, one firstly has to define and clearly describe the necessary requirements in order to ensure sufficient quality without excluding potentially attractive suppliers because of too strict criteria. Here, especially the way of designing bearing arrangements and the sensiviy for failures have to be considered. Apart from endurance, further properties like friction or noise emission can be relevant too.

Auditplan
Product audit

An important part of each supplier evaluation is the product audit at the the factory. Technical requirements to the products result in expectations concerning production methods, plant organization and last but not least inspection and verfication during production including documentation.Scope and frequency of audits have certainly to be adapted to given requirements and size of the related plant.

Apart from supplier evaluation, the audit helps during their development. If minor weak points will be detected, we typically provide immediate support for definition and implementation of required counter measures. Furthermore, possibly adapted quality concepts are based on audit results. E. g. in some cases, it can make sense to cover minor risks based on quality management of the supplier by increased effort durign incoming inspection.

Erprobung
Bearing test rig

Apart from audits, testing the products themselves is absolutely essential which applies to both samples for initial approval and regular deliveries. Micro-geometry of raceways such as circularity, roughness and profiles are highly relevant here and have to be measured by high-resolution instruments. The same applies to material quality, especially the amount of non-metallic inclusions and carbide distribution. Here, one can expect most differences between high quality and cheap products as extremely low prices can only be achieved by using less qualified raw material.

In case of high requirements on product reliability, lifetime tests are recommended. For this purpose, numerous test rigs are available, on which a broad spectrum of parameter combinations may be realized in order to carry out the test runs as close to reality as possible.


Suppliers of large industrial gearboxes

Industrial gear box
Industrial gear box

Large industrial gearboxes are typically produced in small series while frequently, individual solutions are requested which require close collaboration between supplier and customer. Here, especially clear communication of requirements, verification of technical concepts and of course the general assessment of production processes are essential.

Therefore, supplier development begins with definiton of technical specifications which apart from detailed description of the application and expected operation conditions includes the scope of documentation as appendix of quotations as based on these documents, differents quotations and technical concepts can be compared with each other. Here, one has to ensure that definition of requirements do not restrict the space of solutions more than necessary.

Finite elements analysis
Finite elements model

Then, approval of concepts required verification of design calculations which applies especially to gearing (according to DIN 3990), shafts (according to DIN 743), bearings (according to DIN ISO 281) and housing (according to FKM). For the latter one, finite elements analysis is typically necessary. Apart from that, one has to check whether drawings of parts match design calculations and whether e. g. each stress concentration detail of shafts have been considered appropriately.

As a matter of course, audits are essential too while scope and complexity depend on the related product and design methods. During the audit, one has to pay special attention to any manual process as those bear the highest risks for mistakes. This applies e. g. adjustment of bearing clearance and contact patterns or pretension of bolts.

Endoscope
Endoscope

A few weeks after start of operation of such gearboxes, one can assume certain running-in and then, it will make sense to conduct a thorough inspection and endoscopy including verification of contact patterns. Apart from that, it is recommended to measure and record vibration behaviour by accelerometers at defined operation conditions. Then, results can form part of acceptance protocol and can be utilized as reference for subsequent measurements. Especially measured vibration signals can help to either verify or falsify possibly subjective noise feeling.


Other products

Pressure relief flap
Pressure relief flap on test bench

Our competence is not limited to bearings and gearboxes. We will be pleased to support you during assessment of suppliers for pumps and motors as well as foundries and many others. Inspection of special machines or aggregates such as pressure relief flaps are regular services of ours which become relevant especially in case of increased safety requirements or if special standards have to be fulfilled like e. g. in oil and gas industry.