Build Your Own Cnc Plasma – I always thought a CNC plasma table was either too dangerous or too expensive to run in my home shop, where I don’t actually build anything for profit. While the plasma table presents some unique challenges, such as dealing with the metal fumes it produces, I can officially say that I was able to “affordably” (<$4k) and build one safely. And I'm glad I did! Plasma cutting designs from mild steel is the most fun I've had in a long time. I might even say I like plasma cutting more than 3D printing (surprising, I know). Unlike factories, plasma cutting parts does not require careful planning. I simply loaded the .DXF file into my favorite CAM program, generated some G code, and the plasma cutter was off to the races.
Although there are many affordable CNC plasma tables on the market, it is important to remember that you get what you pay for. I can usually squeeze a little more mileage out of my money by getting my own parts and building the unit/machine. However, this is not always true, especially when you break a component during construction or if you buy the wrong part. What I can promise you is that building your own plasma cutting table will give you a better knowledge of how your instrument works, allowing you to troubleshoot and solve problems quickly.
Build Your Own Cnc Plasma
This CNC plasma table was built in collaboration with OpenBuilds, a company that sells open source linear actuators, CNC machines, and many other tools that support the Maker community. We were able to adapt their existing Lead Machine, normally used for CNC routing, for plasma cutting. This requires a few more changes than just replacing the router with a plasma torch, so be sure to watch the video and read additional information below to learn about all the steps required for this conversion. Since this plasma table is based on a Lead Machine, it is unofficially nicknamed Lead Plasma.
Part 1 2×2 Cnc Plasma Cutter
For full transparency, the parts needed to build the main plasma were given to Dr. D-Flo by OpenBuilds for beta testing. This project predates the official release of the Main Plasma kit, so you must purchase the parts individually from the BOM below. I will update this project when the kit is released.
BOM may contain affiliate links that provide returns to Dr. D-Flo. These funds are used to pay for this website and future projects.
Building a CNC table is well documented because it is based on machine lead. Installation instructions for this machine can be found here. OpenBuilds has also posted a YouTube video on the mechanical and electrical side of this build.
Plasma cutting is a 2D process because you cannot control the depth of cut (on hobby level machines). Either you cut material or you don’t. For this reason, a motorized Z axis is not required for plasma cutter functionality. A manual slide that allows you to adjust the distance of the torch to the material is sufficient and many budget plasma cutters do not use a linear Z actuator. However, this manual torch height adjustment must be done at the beginning of each cut because not all materials have the same thickness or flatness. Additionally, the material can become warped during the cutting process, so you may need to pause the plasma cutter between tool passes to adjust the torch height.
Construct A Cnc Plasma Cutter For $3000
The floating head is a simple assembly that automates the initial height adjustment of the burner, but it has the added cost of requiring a motorized Z-axis. In an ideal world, the switch would be located at the bottom of the nozzle. As the Z actuator moves the torch closer to the material, the switch will eventually trip, signaling the computer that the nozzle is near or touching the material. Unfortunately, with this setting, the power switch will turn off as soon as the plasma flow is started. This is a leap from the previous scenario, but imagine if the plasma torch was placed on a spring-loaded carriage and the aforementioned switch was placed directly above this unit. In this setup, if the Z actuator continues to push the torch down after the nozzle touches the material, the torch will move up as it is on a spring loaded carriage. Movement on this cart will then trigger a switch. As the Z actuator moves up to retract the plasma torch, the spring (and gravity) will force the torch down to its original location. It’s a good idea to study the accompanying animation to fully understand how the floating head works if you’re still confused.
Mounting a plasma torch to a floating head can be a tricky business, especially when trying to use a handheld flashlight. If possible, I always recommend using a machine torch (sometimes called a penlight) as the straight body of this type of torch makes it easier to attach to the floating head. Often you can tie the flashlight to the floating head. I prefer to use a 3D printer to make the handle. However you choose to mount the torch, it’s important to give it room to bounce if you drop the Z-axis into the table, otherwise you risk breaking the torch in half. For those with expensive machine burners, a magnetic separator mount is a good investment.
For most people, it is not in the budget to buy a machine torch. It is more cost effective to use the handheld flashlight that comes standard with most budget plasma cutters. The problem with this approach is figuring out how to hold the torch while keeping the nozzle perpendicular to the workpiece. The most common mounting point is directly above the shield cup (the ceramic part that protects the interior from the heat of the plasma flow). The handle holding the torch at this time must be heat resistant. As you can see in the video, I used heat treatable PLA for the handle, which has worked well so far.
Plasma tables are usually too large to require their own stand. They also require a wide berth from other shop equipment because they emit sparks and metal powder. When building a stand, it is important to choose a sturdy design that can support not only the weight of the CNC frame but also the material to be cut. I have already cut several pieces of mild steel weighing > 100 lbs (45 kg). My garage doesn’t have a lifter, so I have to slide the material onto the plasma table and the stand has to withstand this shear force.
Building A Cnc Router On Preexisting Cnc Plasma Cutting Table
I have found the OpenBuild stand which uses 40×40 aluminum profiles for the legs and 20×60 aluminum profiles for the bars to be very supportive and stiff. The rack design can be found in the SketchUp file in the download section. I added wheels so I can roll the plasma cutter out of my garage when cutting dry material. I created an STL file that allows standard wheels to be attached to the bottom of the 40×40 aluminum profile, which is also in the downloadable section.
The plasma cutting process produces fine particles that can damage you and nearby electronics. If you work in a small shop, such as a garage, you need to take steps to prevent metal dust from contaminating the air in your shop. Two options for smoke management are drop tables or water tables. A draft table uses a fan to draw the smoke into a duct under the work table before expelling it. Drop-in tables are expensive and usually only available at large fabrication shops. Another option for smoke management is a water table. As the compressed air from the burner blows down the molten metal, it comes into contact with the boiler. Instead of being aerosolized, the metal dust is trapped in the water. A water table is simple, cheap and effective, that’s why I used it for this build.
To contain the water I used a stainless steel drip pan, which is meant to sit under the washing machine and collect the water, but it works fine for plasma cutters. The only problem with this pan is that I have to use a siphon to drain it. Welding the drain on the bottom is definitely a future project. The material I will be cutting rests on the sacrificial blade, which is a 1 3/4″ flat bar of mild steel (1/8″ thick). To keep these slats upright, I used right angle brackets attached to the aluminum extrusion platform. It is best to avoid using aluminum or stainless steel for slats as both produce harmful gases when plasma cut.
When I really enjoy a project, like this CNC plasma cutter, I do it immediately