Designing Parts to be Plasma cut
When designing parts to be plasma cut its important to take into account a few limiting factors that the process introduces. While plasma cutting is generally fairly accurate, for most jobs I figure about +/- 0.015". It can be more accurate if close care is taken, like start with fresh consumables and tune the kerf width, cutting feed rate, cut amperage, water level, and torch height in as close as possible. The closer each variable is too its "peak value" for the thickness and type of metal of the work piece the more accurate the cut will be. In reality, you can hold plasma to +/- 0.005" but probably only for 1 or 2 parts after you waste about 4 of 5 parts getting it dialed in, so all practicality is wasted there. The frustrating thing about plasma is every variable effects the other. Kerf width (the diameter of the cutting jet) actually gets bigger and gets out of round as the consumables wear. Amperage and Feed rate change Kerf width. So if your feed rate is left the same a higher amperage will produce a wider line cut. If your Amperage is left the same and you cut with a faster Feed rate it will produce a thinner line cut. So its not a cut and dry process but it is very viable if you keep these limiting factors in mind while you design your part, Don't set your self up for failure! Give your self a good 0.020" around bolt holes and don't try to cut details that are too close together.