Plasma Cutter Use Instructions:
Information on the plasma cutter can be found in a few places. First if you are reading this you are in one of two correct places! The other location to find information on the plasma cutter is on the mindworks site. To find this page please navigate to the mindworks home page. From here look to the left menu. In this menu there is a tab that reads Machine Shop. Select this. After selecting this you will be taken to the Machine Shop page. In the top horizontal menu there is a section that reads Outsourced Operations. Select this. This will bring you to a page with a table listing all the outsourced operations at the University of Idaho. In this list there is a pdf and DOCX file for the plasma cutter, laser cutter, and water jet. The plasma cutter is on campus, while the other two are not available from campus and will need to be outsourced. Information on companies that provide these services can be found in their respective documents.
The design of a plasma cut part can be created in Solidworks, Adobe Illustrator or a variety of other software programs. The Plasma Table Technician uses DXF files to communicate with the plasma cutter interface. If you are having trouble creating a DXF file from Solidworks please contact your project instructor. If Illustrator is wished to be used, the MILL in the campus library can be referenced for direction on how to use this program.
Plasma Cutter Capabilities.
Plasma cutting is based on creating an arc with the surface it is cutting to melt the metal and then remove it with a blast of compressed air. A plasma cutter can only cut metal that it can arc with. Depending on the alloy you are using the plasma cutter may or may not be able to arc and then cut the material. Some common materials a plasma cutter can cut are steel, copper, brass, aluminum, and many various other alloys. The plasma cutter on campus is capable of cutting material up to 0.375” it is recomended that the plasma cutter not exceed 0.25".
Tolerances and Limitations.
A plasma cutter is typically accurate to 1/16th of an inch. Keep this in mind when creating a part and plan for some minor error from the plasma cutter.
The accuracy of the cut may vary slightly and if a higher tolerance of a hole or feature is needed this will need to be done on a drill press or by some other means. Additionally no hole in any material should be smaller than the thickness of that material... For instance, if there is a 0.25” thick sheet of steel the smallest diameter hole allowed to be cut into it is 0.25” measured in the DXF file. Larger diameter holes are acceptable. This does not include the measured tolerances. Therefore if a 0.25” diameter holes is required in the material a 0.25” hole must be in the design of the DXF file and therefore a hole that is roughly 5/16th of an inch will be produced. If a smaller hole is needed a thinner gauge metal will need to be used. This continues throughout the thickness range of the metal. If a smaller hole is needed either use a thinner piece of metal or use a different tool.
Plasma cutting is best for large shapes and low tolerances. Once a part is roughly cut, then a part can be worked further by more accurate tooling if necessary.
Do not cut “Pilot Holes” in material to then have those same holes drilled further to a larger diameter or to a tighter tolerance. Plasma cutting is a process that alters the microstructure of the material being cut and produces a heat affected zone which hardens the material making it more difficult to machine.
The following outlines the thickness of various gauges of metal for reference to the minimum hole diameter allowable.
Thickness of Steel in Gauge:
Gauge of material
After about 14-gauge steel, the measurements of the thickness begin to be spoken of in fractions of an inch. The smallest of these is generally 1/8th of an in. Here again the smallest a hole can be cut in this material measures 1/8th of an inch in the submitted DXF file. If the thickness of other gauges of steel less common than those listed above is absolutely necessary some work can be done to see if they are available, but this will most likely not be necessary and the selection above should meet your needs.
After Design is Complete:
Once you have completed your design considering all the above information, and converted it to a DXF file you can email your team leader this and he will contact Tadd (The plasma cutter table technician) so he can cut it. Depending on the complexity of the design and the logistics of holes, cuts, and piercings made by the plasma cutter there may need to be slight changes to have a successful prototype completed.
Paying For Your Part:
In the Capstone section of the Mindworks page there is a central column labeled “Purchasing.” In this column there is a link to “Purchasing Instructions.” In this pdf, under “Internal UI Sources” there is contact information for the plasma cutter technician Tadd Wheeler. A conversation directly with Tadd can be started by the designated team coordinator for payment of the work he does.
The following document is a rough estimate for the costs of various materials and the hourly charge of the shop. This may vary slightly. But can be used as a rough estimate.
Sourcing material to be used on the plasma cutter can be done and is encouraged to be done through the “Shop Stores” also listed under “Internal UI Sources.” Additionally, Mundy's in Moscow, Bill's Welding in Pullman, as well as Pacific Steel and Recycling in Lewiston can be contacted for purchase of raw materials. Their contact info will be listed below. If purchase of materials is done through a supplier separate from the University, transportation of the material will likely be needed. There are no options for a University vehicle to be used, but this can be addressed with your lead instructor and a creative solution can be implemented.
Suppliers Contact Information:
Bill's Welding 700 South Grand Pullman, WA 99163 Phone: 509-334-2222 Website: http://www.billswelding.com/home
Pacific Steel and Recycling 604 12th St. North Lewiston, ID 83501 Phone: (208) 743-2181 Website: https://www.pacific-steel.com/
Mundy’s Machine and Welding 2650 US-95 Moscow, ID 83843 Phone: (208) 882-5648