FAQ’s

General Information

• Do you have a representative in my area?

  In order to provide you with the most timely service and most accurate information, all inquiries are handled directly by our in-house staff. If your situation requires a visit to your facility, we will gladly arrange for one of our staff to meet with you.

• Do you have what I need in stock?

  We carry a large inventory, so it is possible that we have what you are looking for in our warehouse. If not, our lead times are significantly shorter than is common for the industry.

• What if I don’t see what I need on your website?

  Ask us! Chances are that we can help, even if you don’t see the item on our site.

• What is the best way to send a print to MTS?

  We can accept prints by mail (Midwest Tungsten Service, 540 Executive Drive, Willowbrook, IL 60527), fax (1-630-325-3571), or e-mail (mts@tungsten.com). We accept all cad formats. To speed your quotation, please ensure that prints are properly and completely toleranced.

• When will I receive my quotation?

  We understand the rapid pace of business these days. Our goal is to return a quotation to you within 24 hours of receiving your request. You can help speed this process by tolerancing prints, indicating purchase quantities, and specifying material compositions in your inquiry.

Vacuum Metallizing

• What is vacuum metallizing? Vacuum evaporation? Vacuum deposition?

  All of these terms can be used to describe the same process, with vacuum metallizing being a more specific case. Within the confines of a chamber which has had most of the air removed, metals or other materials are heated until they vaporize. This vapor travels about the chamber and condenses on surfaces within the chamber, forming a thin film.

• Why is the deposition performed under vacuum?

  Two reasons – to lower the boiling point of the material to be deposited and to allow the subsequent vapor to travel about the chamber without interference from air molecules.

• How great a vacuum is needed?

  Typically metallizing is performed under a vacuum of at least 10E-4 (.0001) torr. One torr is also known as one millimeter of mercury. Atmospheric pressure is 760 torr.

• How is the evaporation material heated to boiling?

  In the most simple case, a wire or sheet of metal is used as both a container and heater for the material to be evaporated. By running a current through this metal, enough heat is generated to cause vaporization of the evaporation material. Tungsten, molybdenum, or tantalum are the usual choices because they have melting points higher than most evaporation materials.

• Are there other techniques for vacuum deposition?

  Yes. Besides using resistance heated thermal evaporation sources, methods such as electron beam, cathodic arc, and sputtering can be used. These methods have a much higher capital equipment cost. They may be appropriate, however, for materials which would decompose or degenerate upon heating.

• What kind of materials can be evaporated?

  Many metals, compounds, chemicals, and alloys can be evaporated and/or deposited. The material will dictate which of the techniques listed above should be used. Please contact us for details on specific materials.

• What materials are commonly vacuum coated?

  Plastic is probably the most common material coated. Often this is to enhance the appearance of a plastic part or to increase its reflectivity. A metallic coating may also be used to reduce electromagnetic or radio frequency interference in electrical or electronic devices with plastic housings. Lenses can be coated to improve performance, integrated circuits can be created, film for food packaging is often metallized to improve its barrier properties.

• Can you describe the characteristics of the deposited film?

  The deposited film is typically very thin, and composed of small platelets formed when the vapor hits the substrate. Films are usually in the neighborhood of 1000 angstroms thick. Films may contain small pinholes. Films are generally fragile and should be protected with a topcoat. There are exceptions to this, like SiO films. Films take on the character of the substrate underneath. Reflective films must have a smooth substrate. Film thickness can affect opacity, color and reflectivity.