If you’re new to a CNC plasma table, the three things that cost me the most on my first paid job were: not checking the cut settings before hitting Play, not squaring the sheet on the table, and nesting the plates too close together. Here’s what happened and what I’d do differently.
So there I was, all fired up for my very first real plasma table job. Someone trusted me to cut four 5’x10′ sheets of steel, each nested with 84 plates (with slotted holes, of course), for a total of 320 plates. That’s 320 chances to screw something up, and believe me, I gave it a good try.
We loaded the first sheet on the table, loaded the plate layout into the computer, hit that beautiful “Play” button and watched the magic happen. Or so I thought.
A few hours later all the plates were cut. Mission accomplished, right? Not so fast.
Lesson 1: Why check your settings before you hit Play?
In all the excitement, I missed two small details:
- The plate thickness was set to 3/4″ instead of the 3/8″ I was actually cutting.
- The torch was on Fine Cut instead of Fast Cut.
Oops.
The result? The machine chugged along for four hours, stopping again and again, fighting the wrong settings while I tried to change things in the middle of the run. Pro tip: that doesn’t work. You have to stop the job and reset.
But hey, the first sheet got done. A hard-won victory.
Lesson 2: Why does the sheet need to be square?
On the second sheet I did it properly. I squared the sheet on the table using 2″x2″ tubing, lined everything up, and fixed the settings:
- 3/8″ plate thickness
- Fast Cut mode
The estimated cut time dropped to 1 hour 38 minutes, almost half. The cut quality was much better, too. We wrapped up for the day feeling pretty smart.
Lesson 3: How much space should be between plates?
That night I was lying in bed and couldn’t stop thinking: could it go faster still?
Then it hit me. I had left a 1/4″ gap between every plate, so the torch was cutting all the way around each part, and every shared edge was getting cut twice.
So I opened AutoCAD, measured the plasma kerf (about 1/16″), and offset each plate outline outward by 1/32″, half the kerf. Then I nested the plates right up against each other with no gap, exported the new layout as a DXF and sent it to the controller.
The result? Cut time dropped to 38 minutes. That’s 3 hours and 20 minutes saved on every sheet compared to the first one, just from changing the layout.
We hit Play, and this time the plates came out perfect.
The moral of the story
Your first plasma job is a rite of passage. You will mess up, but you’ll also learn faster than you ever thought you would. And I made my first dollar on it. That’s a win in my book.
If you’re just getting started, I put together a step-by-step guide to cutting steel plate on a CNC plasma table with Optimum CNC, and here’s how I export plate DXF files from Advance Steel for the table.
If you run a small shop, my toolbox talk topics for the steel industry make safety meetings easy. Base plates are a classic first plasma job, so here’s how I model base plate connections in Advance Steel.
