I occasionally work on projects for food grade facilities and the material of choice is stainless steel - mainly 304. I usually send out parts to be laser cut and I have used a manually-operated mill on occasion. After seeing the precision parts made out of aluminum, I began to wonder about making that OX or ROUTY type CNC that would work for stainless parts. I know that serious milling done on stainless requires a very rigid frame and usually has a stationary spindle with moving table, like this: But I also see some stainless cut on a gantry type CNC using slow speeds and multiple shallow cuts, like this: I'm curious if anyone has tried using an OX or something similar on stainless? What were the results? Here are some things that I think will be key to success: - slow speed: 10 - 20 ipm - shallow cuts: ~.02" - temperature control: continuous cutting fluid spray / air stream http://www.ebay.com/itm/mist-coolan...052?pt=LH_DefaultDomain_0&hash=item19efd77844 - solid spindle with a solid mount: http://www.ebay.com/itm/CNC-2-2KW-S...497?pt=LH_DefaultDomain_0&hash=item3a93347021 - a bit designed for use with stainless: http://www.ebay.com/itm/ONSRUD-83-3...401?pt=LH_DefaultDomain_0&hash=item33906c9991 Any thoughts on this? I like the OX style, but will be able to get precise results? Will there be too much vibration? Will the added strain of cutting stainless versus wood or aluminum result in stretched belts and more back lash?
Sorry, I can't offer any direct experience but I would like to ask about the nature of the parts you are cutting. Are they largely made from large thin sheet stock or are you milling down small thick blocks? This will determine whether to use a gantry system or a movable table/fixed head. Remember, for a movable table you need to have an area 4 times the table size to be able to get all parts of the table to the cutter and having to reach out a great distance with the head to get to the center of the cutting area can take a greater toll on the overall stiffness of the system than going with a properly stiffened gantry system. You'll note from the two videos you posted, the system used was based on the nature of the material being cut.
Mainly I will be cutting square tubing with 1/8" wall and plates that are generally 1/4" but sometimes 3/8". Generally the lengths will be up to 40". That is part of the reason I am interested on gantry style - a moving table will have to be very large. My thought was to make a gantry style that is narrow (maybe 18" wide) and long (like 48") and allow for longer tubing to cut that will hang over the ends.
I've had a very heavy duty CNC router in the past and attempted to cut SS 1/8 and it was a challenge. You need a lot more rigidity than what you typically find with CNC routers. Aluminum is tough enough to cut, but SS requires liquid cooling and slower feed rates. I would outsource SS work to a laser cutting shop personally.
Chris, Can you tell me what happened when you were cutting the 1/8 SS? Can you take a look at the top of the thread and see what you think about the parameters I am intending to use. The spindle I'm looking at is liquid cooled, feed rates are slow and shallow cuts, I have located a cutting fluid mister, and am planning on bits that are specially designed for SS. I am familiar with working with stainless... even drilling a hole is a challenge if you don't know what you are doing. I appreciate your feedback.
