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GCode is Complicated
G-Wizard Makes it Easy

5 Awesome Ways to Use a GCode Editor Simulator With CAM

Jan 7, 2017   //   by Bob Warfield   //   Beginner, Blog, GCode, Software, Techniques  //  1 Comment

cnc g-code

I get asked this question a lot:

Why would I need a GCode Editor Simulator when I’ve got CAM and it has a Simulator too?

For many CNC’ers, they think CAM means they’ll never need or want to deal with g-code. So why would they ever consider having a G-Code Editor / Simulator like our G-Wizard Editor?  Wouldn’t it be redundant?

Honestly, to me that’s like asking why I’d need bacon if I already have eggs for my breakfast. The two really do go together extremely well (eggs and bacon or CAM and GCode Editors–both go well together!).

We have run a survey for a long time that asks CNC’ers what their knowledge of g-code is, and here are the results:

how many cnc'ers know gcode?

Look how few CNC’ers can’t really work much with gcode…

Look how few CNC’ers really can’t work much with gcode.

Most CNC’ers discover that if you’re going to be into CNC, you owe it to yourself to pick up a decent grasp of gcode.  It really is useful and fun.

Here’s how folks use GW Editor with CAM:

Verifying GCode is Correct Before it Goes on the CNC Machine

A backplot shows you what the g-code is going to do…

Many CNC’ers check the code that comes out of their CAM before they put it on a machine to save time.  All CAM has bugs and sometimes it can be hard to see what’s happening in the CAM.  This article explains more fully:
The best CNC’ers always run their CAM-generated code through a full g-code simulator before putting it on the machine. And no, as the article above demonstrates, the simulator included with your CAM software doesn’t count.  It operates off the same geometry produced by the toolpath, not off of g-code like your machine.
The postprocessor uses that geometry to create the g-code.  So any problems downstream of the geometry will be invisible to the CAM package’s simulator.  This article describes just some of the things a good stand-alone simulator will do that your CAM simulator can’t.
But it gets better.  A good simulator goes beyond just a backplot–it makes all sorts of other error checks just like your controller will.  They can also tell you all sorts of useful statistics like what the maximum extents are for each coordinate. For example, the maximum Z depth the program will descend to.
The maximum Z-depth along with the length of the longest tool will tell you how high to set part zero if you want to “cut air” to prove the part, for example.  Handy stuff.

Making Little Fine Tuning Changes Much Faster than you can with CADCAM

fine tuning gcode cnc programs
Fine tuning your g-code can make a big difference…
Lots of times you get the g-code from CAM on the machine, and as you’re running it, there can be little changes you’d like to make.  Change a tool number, adjust feeds and speeds, and so on.  You could go all the way back through the CADCAM cycle to do that, or you could use a g-code editor to make these kinds of fine tuning changes quickly and easily.
Some kinds of fine tuning are hard to impossible to do in CAM too.  Those programs can be pretty stubborn about how they want to generate a toolpath given some geometry from a CAD model.  GCode editing can give you total control.  Maybe you just need to change a retract motion a little bit to clear a clamp, for example.  Or, slowdown that one certain point on the tool path that always lets out a sharp chatter squeal without having to slow everything else down.
Another great example of little changes is all the little tweaks that come up when you’re debugging a new production program or have a problem in the middle of the program you need to recover from.
Suppose the program is set up to run 8 parts at a time, and the endmill breaks after 5 parts have run.  Do you rerun the whole thing and just let it cut air for the first 5 parts to finish up the remaining three?  That’s really slow and painful. With a few minor tweaks to the g-code, you can run exactly what needs to be run and skip the rest.
That kind of situation comes up all the time during production.  But, it also comes up constantly when making one-offs.  In fact, it’s even more likely because you don’t have the luxury of perfecting the program across lots of parts.  You need it to work for just one part.  So, when things go awry, how do you rework things without constantly going back into CADCAM, a very slow process?
Or, let’s go the other way.  Is it easier to lay 8 parts out on a fixture and CADCAM all of that, or just let the CADCAM deal with 1 part and use a little g-code programming to do the rest?  The answer is, it depends on the job, but it can often be easier to use the gcode.
If you know a little g-code (and tools like GW Editor make that so much easier), you can do an amazing amount just tweaking and correcting the CAM-generated g-code.

Learning GCode

It’s useful to read g-code well whether or not you write much of it.  G-Wizard Editor is an awesome learning tool for g-code.  We have a lot of educational customers using it.  Just the “Hints” feature that explains each line of g-code in simple English makes it a powerful learning tool.
If nothing else, you can’t make simple changes to g-code until you’ve learned a bit of g-code.  But beyond that, being able to use g-code can really speed up tasks like Job Setup.  Being able to use MDI efficiently to make the machine do exactly what you want as opposed to jogging it everywhere during setup will save an amazing amount of time once you get a little bit good at it.
We even offer a Free G-Code course that’s full of examples using G-Wizard Editor to make learning the gcode easy.

Making Simple Parts Without CADCAM:  Conversational CNC

Sometimes you want to do something really simple, and running CADCAM seems like way too much trouble.  For example, you need a simple square bracket with a few holes in it.  If you had a manual machine, you could’ve made the silly bracket in the time it takes just to do CADCAM.  This is where GW Editor’s Conversational CNC feature shines.  It makes doing all this simple stuff with CADCAM really easy.
More about Conversational CNC here:
Conversational CNC coupled with a bit of gcode work is also handy used in conjunction with CAM.  For example, GW Editor has a special Deep Hole Cycle generator.  It lets you completely specify a custom deep hole cycle that uses all sorts of tricks to drill deeper holes that aren’t built any of the canned cycles already in the machine.
The next time a deep hole is giving you trouble, try using a custom deep hole cycle to fix it.

Doing Special Uber-Cool Things That Win Big

Eventually, everyone discovers there are really cool things you can do with g-code that CAM just can’t help with.  So, they start adding g-code to the CAM-generated programs to do these things.
What kinds of things?
These days it’s all about automation.  The more you can automate, the faster and cheaper your manufacturing will be.
You may never need to do these automation tricks, or you may think they’re the bee’s knees.  Either way, you can learn about them here:
I hope that helps you to understand all the cool things a G-Code Editor can help with.  If you’d like to get started messing with a GCode Editor Simulator, give our G-Wizard Editor a spin.

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5 Awesome Ways to Use a GCode Editor Simulator With CAM
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1 Comment

  • Thank you Bob for the article and for your website. I agree an editor/simulator is very helpful. Two examples I can think of. One, in my CAM software, HSM, if I am using G54 and G55 for example, I can program off a single part, but have one side in vise A and then flip the part and place in vise B. The CAM will show it machining both sides of the part, but not like it really is. Of course I could program in an assembly. But the simulator will show the G54 and G55 as it will be on the machine. Second, I have an old machine at home that does not use G54, but G92. I currently manually edit my programs to do this. Thanks again.

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