2 years with the Torchmate 2×4 CNC Plasma cutter

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.

Digital manufacturing is extremely important in today’s workplace and the CNC plasma is a great example.  As a teacher of manufacturing it is important to work with professional equipment, but it is also equally important to work with tools that offer issues that make the student problem solve.  The nature of CNC plasma is relatively inaccurate.   The way I describe the CNC plasma to students is that it is like a swirling upside down candle.  The flame is not straight nor does it always flicker perfectly vertical.  After giving instruction on milling machines and CNC mills, the instant feedback is annoyance from students, but once they learn to work within the capabilities of the tool, they are astounded at what they can accomplish.

I guess I am leading the first part of this review in the idea of CNC plasma, rather than the Torchmate specifically, but I will get there.  Here are the issues with CNC plasma cutting.

  • Kerf width varies slightly
  • Kerf cut is rarely vertical
  • Even light amounts of dross on the undercut can be annoying to remove

In the production world, these issues could be unimaginably huge problems.  Things do not come off of the tool perfectly accurate within +-.001.  In the education world, however, these issues create a perfect learning situation.  If a student requires a 4 inch square within +-.001, how can this be done?  That is the biggest point of learning and if we had better tools like a water jet or a metal laser, this learning would not be achieved.  I personally like the tools best when they are great, but have downside.  This creates an atmosphere of problem solving.  The student mentioned above may choose to cut it out too big and machine it down to specifications, or sometimes they may choose that the plasma isn’t the best tool to use.

This idea is similar to 3D printing.  The best learning happens is when it isn’t perfect.  Is the 3D printer the best tool for project X?  A lot of the times it isn’t, but as long as you are familiar with the strengths and weaknesses of the entire shop, you will succeed in your project.

All of that said, there are ways to really increase the quality of cut with the plasma cutter, but you have to have a good deal of success with the given cut charts prior to leaving the comfort of them.  We have a Torchmate 2×4 table with the auto height adjust and a hypertherm 65 machine and hand torch.  We use the Vectric Aspire software for design work and the torchmate software for g-code creation and machine operation.  I have found that any artistic endeavor a student goes for is extremely accurate for their purposes, but any tight tolerance work needs to be very well planned.  By this, I mean, kerf thickness must be planned well, and good luck making small holes with accuracy.  We have had pretty close to zero luck making an accurate hole less than about an inch in 1/4 steel.  The other piece that is a positive and negative is the auto torch height control.  It allows for cleaner cuts by reading the voltage off of the metal and moving higher and lower to stay at the correct voltage.  The problem with this is that height above material is the the most important part to achieve consistent kerf width and cut symmetry.  Now for most cuts, the product works out perfect, but this has to be planned into the work tolerances.

Even though our machine is a 2×4, you can’t cut 24 inches by 48 inches.  Since we buy 2×4 flat steel, this is a slight annoyance.  We can only cut 22 inches by 46 inches.  We do have a water table and highly suggest it if you plan on running it inside.  That thing makes smoke!  We run the water really high against the steel even touching the steel as it cuts.  the high water makes the smoke negligible and keeps the metal cool at the same time.  there aren’t any negatives.  When running aluminum, we drop the water slightly only so the aluminum isn’t touching water.  This helps create a space for the hydrogen gas to escape.  All the research I found on the aluminum and hydrogen gas has to deal with trapped hydrogen gas, so if you create easy ways for escape you should be fine.  The other safety thing you could do is remove the aluminum sheets after you work with them rather than storing sheets on your table.  That is a safe way to remove any chance of trapped gas under your work piece.

As far as durability, the machine had one broken bearing after a few months, but Torchmate was amazing to work with and took care of the problem fairly quickly at no charge.  At one point I was directly texting pictures of our problems to a tech support person who was sharing them around until they found the problem.  Once they decided on replacing the gantry, it took a few calls and emails to make it happen, but it did, so no complaints.

The hypertherm 65 has been an amazing tool.  We use it for hand and machine cutting, but that cost an extra $500 for the extra torch.  Well worth it to have only one machine for both.  The thing takes a serious amount of air from the compressor, so you will need a pretty good sized compressor.

Now for increasing quality it comes down to quality vs consumable life span.  We have achieved great quality on 1/4 steel through the use of fine-cut consumables.  They were not designed to work with that thick of material, but boy do they cut well in the right circumstances and settings.  The downside is that fine-cut consumables wear fast at those amps.

Recently we started adding chemicals to the water to reduce the disgust.  We added Sodium Nitrate for rust prevention and an anti-fungal to reduce mold.

We added a cut welding screen to the gantry to follow with the cuts and protect the rest of the class from the torch light.

Lastly, we recently learned about cut direction and the need to have everything cut on the right side of the torch.  If you want specifics on how to prepare cuts in the software, we added a blog post about prepping files for the CNC plasma.

Overall, we have been very happy with the machine and it’s reliability.  I know of some other schools with other machines and they have many problems.  If I wanted to go into production I would take this review with a grain of salt.

 

 

 

 

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