how to introduce CNC & train the team?

Our team has a new mentor who is interested in expanding CAM on the team beyond the minimal 3D printing we do. We improve at CAD each year & have a full assortment of manual manufacturing machines + students who know how to use them. We even built our first fully functional 2nd robot this year (yes!).

As a fifth year team trying to continuously improve, it seems time to broaden our horizons to CNC. We have read through the excellent threads covering which machines are good - thanks to all who contributed to those.

My question here is not about what machine to buy. It is… What are some effective approaches, techniques, lesson plans, etc. for introducing a CNC machine to students and teaching them to use it? Step 1 clearly seems to be having a mentor who is willing to blaze the trail by being the first to learn, and we have that. What do teams who introduced CNC have to share about how to effectively get the team going with it?

Time on the machine seems like it could be important - would it be useful to have a couple inexpensive little CNCs to practice on with plastic? (for example)

Thanks in advance for your advice & suggestions.

Chris

Not super useful to have smaller different machines. Small machines often bring more frustration than success. Stick to one machine and setup process.

Check out the Titans of CNC Academy. I think it’s just what you need. There’s a Facebook group as well.

It seems like you have already taken the first step: make sure students know how to setup and use conventional manual machines. This background and understanding will help immensely when making the step to a CNC machine. No machine shop I know throws a greenhorn right onto a 50K+ CNC machine, and your team should consider the same.

You may even want to create a training course and some kind of certification for the machine and only allow those with the certification to setup (non-certified students can maybe still run programs). The machine manufacturer may even have some of these courses at the ready and could possibly be willing to provide you with the material if you ask nicely. :wink:

A significant portion of your time is going to be spent determining the right speeds and feeds for your different tooling. There are many calculators online, as well as phone apps and dedicated software (some of them free as well). If you have a mentor familiar with CNC/CAM, you will be way ahead of the curve.

As a general rule (and something we have been slowly trying to teach our kids), use the shortest, most rigid tool you can for each application. Yeah, you may be able to get a lightening pattern on both sides of your 2 x 1 in one setup if you use a long endmill, but the tool will scream for mercy the entire time no matter what speeds and feeds you use. That vibration, known as chattering, is also absolutely horrible for tool life.

This should be known if your students already know how to use a manual machine, but if you are making repeated parts, rather than finding your zero after every part, use a vice stop. Over the course of the season this will likely save you hundreds of hours.

If you need a pattern on both sides of the part, consider using a program stop (M0) and having two separate parts of the program. Run one side, flip the part and push it against the endstop, and continue running. Be wary of the orientation of the part when you flip though.

My personal recommendation before jumping right into a CAM package like Fusion, HSM Works, or any of the others: Most machines have a conversational CAM portion to them where toolpaths are created on the machine itself. I highly recommend getting familiar with the machine using these conversational programs. Our team has found we can do about 75% of our milling and drilling using conversational, which saves a lot of time. Often we can more quickly write a conversational program and run it than we can make the piece on a manual mill.

Hope this helps a bit!

Thanks! Just the kind of resource I’ve been looking for.

Our team has a new Tormach mill which wasn’t delivered in time for this seasons build. So it’s still not completely assembled. I think that was actually fortunate because now we have a very high interest by the students in learning during the off season.

We got our tormach last year and didn’t use it during the 2017 season much either for similar reasons. Take some time in the offseason to figure it out a bit and then use the heck out of it next year. If you have any questions feel free to send me a PM.

Cyberphil, Thanks I’ll do that. I’ve taken your post and added that information to the post season review we’ll be doing. Which ,unfortunately, will probably be ending this weekend at FLR.

we use the x carve CNC machine, it is good for cutting plates of aluminum and plastic because of the large work area.

Seconded. I suggest Cut2D/Cut2DPro as a good starting point for CAM. Very cheap software with a good number of features and dirt simple to learn with.

And I swear I will be doing that video series on our router trainings this summer…

I tried running aluminum on my previous teams X-Carve but it had trouble getting it to hold a tolerance, plastic works pretty good though. Have you had any luck getting it to cut an actually round pocket on aluminum?

That said, I will concur with some of the other posters, knowing the manual versions of the machines is critical. Once you know that moving to CNC is much easier. Depending on your machine, if all you’re doing is loading toolpaths from your CAD/CAM software, then learning the actual workflow should be quite simple, since you’re basically taking the same steps as the manual machines and automating some of them. If you have a machine that allows manual input (creating toolpaths from the machine itself) and your goal is to teach that, then that can be a bit more of an involved process.

One thing you might try, if you have the budget, is get a “cheap” CNC like an X-Carve to practice on (since the consequences for screwing something up are much less) and once students are comfortable they can move up to a “big” CNC machine.

Adding on to this, if you’re looking at regular CNCs like the Tormach or a Haas, then Fusion 360 does pretty well. I lets you adjust almost all of the parameters that you want to and is very easy to get started with. Learning the basic g-codes before CAM is a good idea too; I went in without any g-code knowledge and it makes simple tasks like modifying code directly a lot harder.

Inventor HSM also works quite well if you’re already using Inventor, it’s quite convenient to be able to make a model and then just change to a different tool tab and have all your CAM settings available in one place. It’s also free for students.

Although I haven’t used it much, so I can’t say to its effectiveness, HSMWorks is the same software for Solidworks.

It’s not the same. I find Fusion to be much better than HSMworks for Solidworks. It recognizes inside/outside contours better, has a better 3D adaptive engine, and gives you access to some cut settings that HSMworks doesn’t have (I forget exactly what though, it’s been so long since I switched). Plus, no tabbing in the Solidworks version. Fusion > HSMworks for Solidworks, but I’ve heard the Inventor version is much better than the Solidworks one.

Chris,

If you need (or anyone else for that matter) some help getting moving in the right direction or have any CNC questions feel free to send me a PM and I’ll send you my contact info. I’m located near Minneapolis, MN so I probably won’t be able to swing by your shop but I should be able to answer or at least find someone who knows the answer to most questions you have. I process and program parts on multiple CNC machines for my day job. We don’t have any CNC equipment for our team (we’d love to just have a Bridgeport at this point) so I can’t offer much advise on how to get the kids up to speed but all can say is take it slow. Prove out each program before cutting a part. Crashing a machine can be very expensive and it will happen sooner or later.

Nathan
Build Mentor
FRC Team #3184 Blaze Robotics

Thanks all for the helpful responses. I have shared them with the mentor leading the CNC opportunity assessment effort.

Fingers crossed we end up going for it; we have a big group of highly engaged sophomores… if we invest in expanding CAM, by the time they’re seniors, who knows what they’ll be able to do.

–Chris

Hi,

Just to give another prospective but on a different machine. Our team is lucky enough to work out of our schools tech shop and we have some fun toys, I mean tools.

Anyway, we do have a CNC machine but find it takes to long to cut parts and have someone knowledgeable to use the machine and baby sit parts as they are being cut. That being said, we picked up a shopsabre plasma cutter two years ago and cut all of our flat stock in house. Once the kids CAD up the part we use vcarve to layout the cut. After that it’s a simple zeroing of the XYZ coordinates and then fit the part on the material. The longest time frame I had on a cut took two minutes. I can also set the tool anywhere on the plate to make use of all the material.

To add, I just figured out a way to cut lightning holes in aluminum tube. Again, it takes seconds for the cut to be complete.

+1 for pretraining a small set of students.

My team is lucky enough to have mentors who work in local machine shops with access to plasma and laser cutters, which means our (ancient) CNC does not get used as often as it used to. Back in the day (okay, 2014), there was a “CNC team” of experienced students who ran all CNC programs. Each year, they would take on some interested new members and train them to become full fledged CNC team members. As far as I can tell, this setup worked out well, with students getting a lot of hands on experience while simultaneously making sure that people who knew what they were doing were present during all CNC usage.

I mentioned that we don’t use it as much now because it’s transitioned into a new role. We do still machine things on it (Lexan, anyone?) but it’s generally run by a mentor or 1-2 seniors, who will round up any unoccupied freshman/sophomores to watch and learn. CNC’s are super cool, and generally awe-inducing to the otherwise aimless new build team member.

I recommend finding a small group of students and a mentor (I think you’ve already got the mentor covered) who are willing to work hard and learn the ins and outs of your new CNC. From there, try to rope in younger team members to learn each year, always under the guidance of the trained members. This ensures that your CNC remains useful from year to year, by ensuring that you always have capable team members ready to use it!

As a student, just reading this document was very helpful: https://www.autodesk.com/campaigns/cnc-handbook

Another thing we’ve done is create a checklist which we taped to the machine that you must go through before running a program. Whenever we encounter a failure, we add a new step to prevent it.

Back in 2016, we invested in a Velox 5050 and it has become invaluable. Being the CNC lead, watching videos like NYCCNC and ThisOldTony has become a great resource. I learned most of my tricks from videos like them.

I totally agree that a basic manual machine knowledge is required to do well with a CNC. The transition from a Bridgeport definitely helps.

As for CAM, we use HSMWorks, and although it has a fairly steep learning curve, it has worked fairly well. The machine simulations after CAM with stock on will be worth it. Saved us a ton of time troubleshooting the program in real life. As for learning HSMWorks, you should try to go over a few main operations: 2D Adaptive, 2D Contour, Drill, and that is about it. Same really goes for Fusion360 if you don’t have Solidworks.

As for feeds and speeds, we have found that a 15 ipm feed and 13k rpm works fairly well for drills (slower for drills above a 7, faster for drills below an 18). We generally use carbide o-flute 1/4 inch end mills. They can be run at 55 ipm or higher at 21k rpm and a 1/8 depth of cut. Adaptive generally uses an 1/8 stepover, and that has resulted in exactly 0 tool breakages.

Anyways, if you are thinking about a similar machine, please shoot me a message.

Best of luck!