What needs to be considered in the quality assurance of drawing parts?

You have found a supplier for your drawing parts. The supplier now has the opportunity to manufacture a part for you, which you can check and on which you can carry out inspections and tests.

If you choose a local supplier or an agent, you will usually have to carry out the checks yourself. If you opt for a one-stop shop, this supplier often has the option of assisting you with quality assurance.

Quality assurance can also be carried out in the country of production

Once the sample has been produced, it must be sent for quality assurance. If this is done in Switzerland, it can take over 6 weeks. The item is checked and reported to the manufacturer if there are any defects, which prolongs the process.

This process can be shortened by choosing a supplier who has the part tested in the country of production. Bossard, for example, offers an ‘offshore inspection’ in which a QC specialist inspects the workpiece on site. Bossard regularly inspects the supplier workshops to guarantee quality.

An offshore inspection saves valuable time. Bossard also tests every new part in its own test centre in Zug to personally confirm the quality.

What tests and inspections can be carried out?

There are a number of tests that can be carried out to ensure that the drawing part meets your requirements. The most important ones include:

• Dimensions: Digital measuring devices allow you to measure the dimensions of the drawing part down to fractions of a millimetre. Of course, it must be ensured that the drawing parts to be checked match the drawings provided. During a check, all dimensions such as material thickness, internal and external dimensions, size of holes, etc. are checked.
• Coating thickness measurement:For parts that have a coating, e.g. a nickel, chrome or zinc flake coating, a coating thickness measurement can be carried out. Using modern measuring equipment, you can measure the thickness of the coating and ensure that it meets the requirements.
• Hardness test: With a hardness test, you can check the depth of cure, hardness profile, surface hardness and core hardness. The hardness of the material influences its resistance, e.g. to bending, abrasion or cutting.
• Material analysis:In a material analysis, the exact chemical composition of the metal can be determined. This means that you can see not only the elements that make up the metal, but also the proportion that each element has in the material. This is important, for example, if the metal needs to have a certain degree of corrosion/rust resistance. In other words, you can make sure that the material corresponds to what you have ordered.

Quality assurance - a must for drawing parts?  

The checks and tests to be carried out vary from item to item and naturally depend on both the complexity of the drawing part and the function it is intended to fulfil. If the requirements for the item are low, quality assurance will also be easier.

If you have large, expensive drawing parts manufactured, you will probably agree: ‘Yes, of course!’ Quality assurance is critical, and we strongly recommend implementing some form of it. This can be self-inspection at your facility or more comprehensive testing at a testing centre.

Only in a few cases is it not worth investing time in quality assurance. This might be true if you are sourcing very simple parts from an already trusted manufacturer or if you are dealing with low-value parts that do not have a critical function in your end product.

Overall, however, especially if you source your drawing parts from Asia or Eastern Europe: Even small errors can become very costly if they are discovered late in the process.