Custom Carbon & Graphite Machining

22 Sep

The Pitfalls of Improper Tolerancing

Imagine a Semco clients sends blueprints to us for an R&D mold that’s never been manufactured before. We would like to assume that the blueprints are accurate, that the tolerancing is correct, and that all specifications have been reviewed by the client. However, Semco has been in business for decades and we know better than to make assumptions about the manufacturing process. Manufacturing flawed molds, for instance, where the tolerancing is off even by a miniscule amount, means wasted time and money for us and the client. To avoid these costly situations (and all the headaches involved), we encourage our...

15 Sep

Graphite Found in Iowa Corn Field

Add huge graphite “logs” to the list of unusual things, like magical baseball diamonds and crop circles, found in Iowa corn fields. That’s what we did when we received a call at Semco from an Iowa farmer who discovered a giant cache of discarded graphite on his property. At Semco, we specialize in precise graphite machining and offer graphite recycling services for the convenience of our customers. An added benefit of this service, of course, is its benefit to the environment. When businesses and individuals who have stored scrap graphite or old graphite machine parts want to clear space and...

04 Jan

Diffusion Barrier Coatings for Graphite Fixtures

Vacuum heat treating shops commonly use graphite fixtures on which to set parts to be treated. Graphite fixtures have excellent thermal stability, allowing them to be used again and again through multiple heat treat cycles. In addition to that, graphitedoes offer significant cost advantages, when compared to other materials used to make fixtures (high nickel/chromium or moly alloy type fixtures)Graphite Fixtures and Ferrous MaterialsIf you are using graphite fixtures, it is important to remember that graphite is carbon, and pure carbon likes to react chemically with metals containing iron, especially stainless steel, to form low melting eutectic compositions at temperatures...

07 Dec

Graphite Fixtures and Eutectic Bonding

Eutectic melting is the process where an alloy of two or more metals, when heated, will completely change from solid to liquid at the same temperature. There are processes in which the eutectic melting is a desired result, such as brazing. There are thousands of eutectic compositions used in brazing applications. They can play a major role when heating a brazing filler metal up to the brazing temperature, as well as when cooling after brazing. During heat-up and melting, the eutectic composition will/should be the first to melt, and because of its narrow melting range (solids and liquids are the...

30 Nov

Aerospace and Graphite

At first you would not really think to put the two together as working partners. Yes…. They are. Graphite is used in the aerospace industry for a wide variety of applications. Heat Treating Synthetic graphite is used as engineered material to create precision machined plates, posts, nuts and bolts along with heating elements and fixtures used in the heat treatment of aerospace metals such as (titanium, stainless steel, and other alloys). The heat treatment process is used to give these metals improved strength, flexibility, or hardness. Graphite PlatesGenerally the graphite plates are preferred as fixtures because they are inert and...