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Hi all

I'm quite new to the world of CNC routing. My wife and I have built a 2' x 4' CNC router and we are designing parts in Solidworks. I'm trying to learn the terminology and software requirements for the next steps. Is my understanding correct - that a CNC controller and a CAM program are separate softwares and that I need both?

If so, I would love to hear others are using, if they like it, and what they would rather be using if they don't like it.

Thanks in advance.

Mach 3 works well for me. There are other choices though, and I'm sure others will be along with their input. My CAD software also has CAM code generation built into it, so I don't have need for an external CAM package.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
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Yes, you are correct, the controller is part of the control system that drives the stepper/servo motor and the Cam system is where you generate the tool paths for you parts and that becomes the input for the controller. You'll also need a post processor which massages the data from the cam system into you're machine requirements. most cam systems these days come with a variety of post posts, or a least the ability to customize one.

Mach 3 seems pretty popular, but if you're a linux guy there's some open source stuff out there to.

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Jim Watts
http://jameswattsguitars.com

I think the two above posts answer your question. There are CNC controllers that is the software to drive the machine. The cam is what makes the tool path and the post processor (which is almost always in CAM software these days) is what converts your tool path over to G code which is what the CNC controller reads.

Since you are new at CNC I'm going to highly highly recommend you do some reading and studying of basic G code (and M code). That way you have a basic understanding of what the machine is going to do instead I standing there with no clue of what's about to happen. Also by understanding the code you can modify programs on the fly at the machine instead of having to go into the cam software, make changes, simulate the cuts, repost, and reload the program.

I'm using Mach 3 to control my machine and while it works most of the time, it does have bugs which seem to come and go depending on which version you're using. I'm also using this screenset for Mach which I highly recommend to anyone using it. Totally worth the $20. Ger, the guy who made the screenset is a great guy to deal with and provides much support.

Mach 3 gives you great bang for your buck, there are tons of plug-ins, and a lot of people using it from whom to draw support but, I'm looking for a better solution. It works for a lot of things but those bugs I spoke of pop up at very inconvenient times. It seems to me if you push the performance of the machine and software that Mach 3 is not such a good choice. I'm currently looking for other options with the Kflop/Kmotion being at the top of my list. I'm not going to upgrade right away but I expect I will within a year. The nice thing about Kflop (which is the controller that Kmotion uses) is that they have a plug-in for Mach 3 as well so I can baby step the switch.

Kflop is about $250 for the controller, plus you'll need a box and power supply for it but the software is no extra charge. If you haven't bought Mach 3 yet, it's only about $100 more and it gives you a much more solid controller from what I hear. It does require that you can program in C to a certain degree to use it though. I know that there are a bunch of guys using it that are doing a fair deal of the programming though so I imagine that within a year one might be able to get the help they need to get it up and running.

As to CAM software, I'm using VisualMill pro for SolidWorks. It's not the cheapest package but it does offer a lot of machining strategies and options that are only available in packages that cost twice as much. I'm also a big fan of the integration into SolidWorks. When I change a model, often regenerating the toolpaths is just one mouse click.

I think if money were no object I'd look into SolidCam or others but, it's about 2x the cost of VisualMill!

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http://www.birkonium.com CNC Products for Luthiers
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I've been using a trial version of solidcam and I have nothing but goo things to say about it. I will definitely be purchasing the software. The fact that it operates within solidworks is fantastic. The models are directly tied together so if you change your solid part it can automatically regenerate your tool path to reflect those changes. No need to import the part into a separate program and redraw toolpath. Also the imachining option is fantastic if you will be removing a lot of material. I was scared of it at first because it takes very deep cuts and maximizes the use of your tool rather than just using the end. I simulated cutting a match plate from a block of aluminum that took around 4 hours to cut, with the I machining toolpath the part was simulated as taking around 20 minutes. I was very skeptical of this because I did not think the tools would hold up to the abuse that they would surely endure with that toolpath. After cutting a core box on Tuesday I am no longer a skeptic. I started with the feeds and speeds set at 20% to be safe and ended up getting up to 70% with no issues at all. I couldn't believe that a 3/8" long reach end mill could withstand cutting through 6061 aluminum at a depth of cut nearly 1" deep traveling at nearly 70 IPM. But it worked. The system they have developed is absolutely fantastic. It is fairly expensive so it may not be for everyone but if price is no option I would highly recommend getting a trial version and trying it out. Plus they have excellent customer service.

Andy,

I am curious as to what bugs have plagued you with Mach3? I have been using it for many years now, and I have to say that it has worked well for me...

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-CyborgCNC
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+1
What Bugs I experienced when first using M3 were mainly RF interference or some electrical inductance. Once I understood the problem the fixes were very easy and inexpensive. Since then ONLY USER ERROR ( BrainFarts) causes me problems.
MK

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I'm outside looking in, just farther from the window than most.

There are 2 major things that I can think of plus one minor one that I run in to occasionally.

To start with the minor - sometimes when I feed hold to check something or clear away chips or whatever and then cycle start to keep going, it seems that mach will lose track of the spindle state. When I get to a tool change, about 50% of the time it will start the spindle back up before it probes the fixed plate! (that may be an error in the macro as well but I'm not sure.

First Major Issue - PC's running windows aren't the most reliable for generating evenly spaced pulses and depending on what's going on in the machine, your steppers can lose a significant amount of torque from an un-even pulse train from the PC. There's a Tormach white paper on the subject but their site is down right now so I can't link to it. When it's back up I'll try and remember to post back a link. This entire issue can however be alleviated by using a USB or Ethernet off board pulse stream generator such as the Kflop/Mach 3 or SmoothStepper/Mach 3 combo.

The second major issue which is the real biggy for me is that there is a bug in the CV mode trajectory planner where under certain conditions, usually a 3D move, Mach 3 will ignore the acceleration settings on one or more axes which will often cause the motor to stall for the duration of the move. This is well documented in several threads on the Mach 3 forum and is a bug in the trajectory planner.

Here's an example: http://www.cnczone.com/forums/mach_soft ... lling.html

If you search on google you can find many more examples of the same thing. I have ruined several parts thanks to this bug. The only way to improve this is to lower your accelerations, fiddle with the CV distance tolerance, lookahead, stop on angle > than setting and pray. Using an offboard pulse generator will almost certainly NOT fix this bug.

To me, this is a super big deal. Ruined parts and longer than necessary cycle times aren't part of my play book. As I said before though, I think these issues only really show up when you're pushing the machine. I cut certain parts at 400ipm to get a nice surface finish on parallel finishing operations and lowering acceleration adds a significant amount of time when you're making several hundred passes on e.g. a bridge. If you're in less of a hurry simply toning down acceleration and top speed can make these issues "disappear". But if you've got a need for speed, it will fall short.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy, I have experienced this on 3D work as well. My Solution was to set M3 in Plasma mode for these. The algorithm used to keep a constant speed while using acceleration and deceleration seems to work much better in this mode. Now that being said, It does round corners if used in 2D. This is to prevent the plasma cutter from stalling and blowing through the material more than any other spot or on a continuous line. Just my observation.

I have tried many 3D multicontoured files and found this mode eliminates the point to point jitters that seem to be found in how M3 interprets code.

Something to try maybe.

as an example for you I have a friend that I converted a small mil to cnc for his business. He wanted to make molds from aluminum and steel for pouring aluminum parts. Skegs to be specific. He makes replace skegs for outboard engines. Once i made the conversion it was a problem when changing directions. The bed plus the plate weighed about 125lbs. this mass movement change was to much for the 600oz steppers at 7+ipm. once going to plasma mode we were able to get 18 IPM when doing steel and 35ipm when doing aluminum. Also were able to improve Acceleration rates of all axis in the process.

These are clam shell type of molds and he gets about 2000 pours per mold, whereas when he was using sand molds, he was getting 4 to 5 units per mold before making new molds. Most large shops wanted $5000 to make the metal molds. He now moved 2 people to another area as they are not needed to make the sand molds. I made a $4000 machine work and it has been in constant use for the past 2 years, it needs adjustment about every 6 months.

Mike

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I'm outside looking in, just farther from the window than most.

I actually had tried that (I think possibly per your recommendation in fact) but I found that it also rounds 3D corners as well (e.g. a sharp 3D-edge). It did increase the average speed of the machine by about double but the rounded edges were not to my liking. Setting a high lookahead without plasma mode on also smooths things out at the cost of edge quality.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Well I thought I had mentioned it before. At least you tried it and found it did somethings correctly for you, but as you said It still has it's limitations. Just a suggestion though.

In fact a while back I asked Mach support if there was a way to turn Plasma mode off and on with G or M code. The answer was no. To bad as this would solve some issues I have as well.

MK

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I'm outside looking in, just farther from the window than most.

I originally used EMC2 with Linix as my controller but switched to Mach3. EMC had a great interface but without support the setup was difficult. I found Mach3 to be very easy to use. The only part of Mach3 that I didn't like was the interface is a little busy for my taste. I like the upgrade that Andy showed earlier in the post that simplifies the interface look which is a real upgrade.

As for CAM software...good luck! Their are some great software packages but the price can get very expensive so it typically comes down to what works within the budget.

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Brad
Avon, OH

Here's the Tormach white paper I was writing about: http://www.tormach.com/engineering_tmc.html

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com