As a high school teacher and user of equipment with teenagers, I feel that we know how to abuse tools. Like all reviews, each reviewer is sharing their personal perspective. This review comes from the perspective of lots of users doing a huge variety of projects with a variety of materials. This isn’t a review from a production shop, but rather a learning atmosphere. Over the last 2 years, we have fired up the CNC plasma about 400 times. We get a lot of use out of the tool.
We finally worked out a new logo. Looking to make class shirts and such.
Here is the new sign for outside our classroom. We CNC plasma cut it out of some 1/8 steel.
As a beginning MIG welder, we all run into problems. Some are settings on the machine, some are operator error. I feel that if you can identify problem welds by looking at them, you could then identify ways to solve these problems for yourself in the future. These “flash cards” also have the answer on the back of them.
Getting going with the oxygen/acetylene torch can be both exciting and overwhelming. It is kinda like learning to drive and learning how to operate a manual transmission. You have to focus on the rules of the road and do a great job driving while at the same time learning about the clutch. It also reminds me of learning to ride a bike. You have to learn to balance and pedal at the same time. If we break these down into individual lessons we can focus on the getting the required skills to move up. In this case I find students overwhelmed with 2 tanks, managing pressures, using a large torch and making great welds at the same time. I brought in this little ‘B’ tank to help with most of that. The ‘B’ tank only uses an acetylene tank and grabs air from the room rather than an oxygen tank. The advantage is easy starting. The disadvantage is a huge reduction in heat. The ‘B’ tank will only be useful for brazing, but it’s main purpose is to teach the skills necessary to be successful with the oxygen/acetylene torch.
We are using Vectric Aspire for creation of vector designs and altering the vectors for quality cuts on the Torchmate. You will be exporting a .dxf file from Aspire once done. You will be using the torchmate software for post-processing and operating the CNC plasma
Once you have your design ready in Aspire, you need to change your vectors so that they cut right on the Plasma
Here are the issues and how you need to deal with them.
Issue #1. The CNC plasma will cut directly on your vector lines and there is a thickness (kerf) to the cut. The kerf thickness does vary, but we have been happy with planning for a 1/16in (.0625in) kerf. However, you can access the real chart here. This requires you to design things slightly larger than you need. The offset tool in aspire has worked wonders to solve this. We have been offsetting at about .035in depending on the requirements of the part. For outside cuts you will need to offset to the outside. For inside cuts you will need to offset to the inside. We have created modeling of what the cut looks like by making a profile toolpath with a 1/16in endmill in the toolpaths tab. Another way to deal with this is to Vector design it purposefully large and grind/mill it to correct tolerances.
Issue #2. This issue is not for all cuts, but something to keep in mind. The CNC plasma takes it’s time around corners which introduced heat to the corners of your cut. This can be a problem if sharp precise corners are needed. This can be solved with the Plasma loops tool. I show the class the need for a square and this is what the toolpaths vectors look like. As you can see the square was offset first, then the plasma loops were added.
Issue #3. The plasma does not start and stop cleanly. This means that you want the plasma to start before your part and end after your part. These are called lead-ins. For the above design I simply cut one of the plasma loops. For inside circles, and any complicated designs, individual lead-ins must be added with the node editing tool. I will create another post on dealing with just this issue as it is slightly more work. One great feature of Aspire is the green node. This indicates where the CNC will start cutting. You can easily change the starting node by right clicking on desired starting node and selecting, “Make this the start node.”
After this, the vector is ready for exporting as a .dxf
This YouTube channel is my go to place for any manual machining help. He goes by the name Tubalcain. He has great lathe and milling skills.
I also like open source machine tools. He finds older training videos and makes some fairly modern instruction videos about manual machining.
Our machinery is a Bridgeport Mill, small Grizzly mill and a Graziano lathe.
If you know of some other great youtube or website instructional places, let me know so I can share them.