Attn: Dr. H. Jack, P.Eng.

Date: 4/14/97

Memo on what I found interesting

on our tour of Sinterform.

Sinterform produces a wide variety of different powder metallurgy parts for several different applications in industry. They produce parts that require small tolerances over a large area such as clutch plates for large trucks that are used in mining. They also produce parts that are simpler with high wear characteristics such as gears for a lawn tractor.

Sinterform uses only certified materials for their powder metallurgy process. They do test parts from each lot of production for the metal characteristic required by the customer. Some of these characteristics are carbon content, strength of the design characteristics, and Rockwell hardness. Another test that is performed is done to identify small cracks or poor surface finish. This test is done by applying a special die on the part which when the part is wiped clean remains in the cracks or flawed areas on the part. The flaws can then be see when the part is placed under a black light.

Sinterform has the ability to mix their own powdered metals so that the desired characteristics can be achieved for a specified part. They mix a lubricant with the powdered metals to help the small metal beads slide past each other in the press operation. They do some regrinding of scrap parts which are then re-mixed by percent with virgin material. The mixing process was albe to be closed off from the rest of the plant. They said that this was partially because the mixing process was very dusty. But the main reason was to eliminate as much as possible the contamination of other powdered material.

The press operation was automated to the point where the powder was added to the die and each part was removed from the press by a mechanism. The parts were then inspected by an operator and if required the key dimensions were recorded. The machines were running smoothly while we were watching them.

Sinterform has several ovens for the sintering process. The ovens are around 35 feet long and the parts slowly move through the ovens on either a chain belt or a system of rollers. An amount of copper is melted into some parts that require extra wear properties, like the lawn tractor gears. This is done by simply placing some small pieces of copper on the part before it enters the ovens. The copper is melted into the part while it travels through the ovens. The addition of the copper gives the parts a golden color when they come out of the ovens.

The tour of Sinterform was informative and helpful in understanding the powder metallurgy process. They seem to be a well organized and well run company.