Burrs on Square Pins Formed From Square Wire: Fixing Each End

Short answer: Square pins formed from square wire can pick up burrs at both ends. The two ends had different causes, so they needed different fixes: one end was solved by changing the die structure, the other by new equipment. Removing the burrs at source cut the share of parts rejected in sorting, and the lower scrap is what made a lower price possible as volume grew.

The part and the problem

The part is a square pin we have made for years in steady production. It is formed from square wire. In the early runs there were burrs at both ends, and the dimensions were hard to keep stable. Parts with burrs had to be sorted out, so a share of every batch became scrap.

Sorting removes the bad parts from the shipment, but it does not stop them being made. The cost of the scrap stays in the price.

Two ends, two fixes

• First end: we changed the structure of the die. That removed the burr at that end.
• Second end: the die change did not reach it. We solved it with new equipment.

The result

Rejects in sorting dropped clearly. As the customer’s orders grew, the lower scrap gave us room to lower the price. The saving came from making fewer bad parts, not from sorting harder.

What to ask about burrs on square pins

1. Are burrs removed at forming, or sorted out afterwards?
2. Is the burr at each end handled separately?
3. What sorting rate is the current price built on?

If you buy square pins or other parts formed from shaped wire, send the drawing or a sample through our RFQ form. We will tell you where burrs are likely and how we would handle each end.

Related: cold-heading defects and their causes · the small parts inside a concealed hinge

How this was written: the case comes from our own production records for one long-running part. The customer is not named.