WASTE TOLERANCE (DETANT) IN SHEET METAL

Hello

I make sure that my blog posts are connected to the previous topic. This may not always be possible, but I wanted to touch on the waste tolerance required when using sheet metal part referencing and auxiliary references in this article.

When you place an auxiliary reference on the plane that acts as the main reference in large parts such as doors, you have to give waste tolerance.

As you can see in the example above, a tolerance of 1.2 has been defined for the auxiliary reference named D1.

Tolerance value is determined according to the companies' own standards. For example, if the part is over 50x30 mm, it is determined by standards such as 0.6, if it is over 70x20 mm, it is determined by standards such as 0.8.

So how do you measure a sheet metal part with waste tolerance?

During measurement on sheet metal parts, there are clamps at these reference points and they are closed. First A1, then A2, then A3 are closed. Then the CMM Probe measures the given auxiliary reference point first. In this example, it measures by going to point D1. If the tolerance is within 1.2, the clamp is closed and the measurement is continued.

In the example below, the waste tolerance is given as ±0.5 and the note "clamp open" is added.

(Thanks to Beyhan Çavuşoğlu for the sample image)

So what happens if the waste measurement is out of tolerance?

The measurement is not continued. Because the tolerance accumulated in the auxiliary reference point will accumulate in different parts of the part when the auxiliary reference is closed. This already means the part is rejected. In this way, measurement time is also saved.

The tolerance accumulated in the auxiliary references without waste accumulates on the functional or aesthetic surfaces of the part and leads to the rejection of the part or quality problems. The auxiliary references with waste provide savings in measurement time.

Waste tolerance is given only to the plane, waste tolerance is not given to auxiliary references given for the direction or origin.