Looking for insight into converting PM25mv to CNC

[Nrpdyer]

Just getting into the hobby and pretty much decided on PM25mv but would like some guidance / opinion / direction please.

The G0704 has a lot of info on the web regarding conversion but I am drawn to the PM machine based on my research of the quality and excellent company reviews. If you would, please recommend a person / company who sells CNC kits. I see several out there but reviews show that these are really hobbyists and I get the sense that although they have good products, they may not be into this full time or may not even do it any more (some comments on really long waits to get the product). I see some kits out there on what appear to be more professional, full time companies but these are quite cost prohibitive. ArizonaVideo, BDtools, HeavyMetalCNC, ProCutCNC, AutomationTechnology, Hoss (who apparently only advises and provides prints), jr7k158 on ebay.
I will only use this for a hobby machine and don’t want to spend a fortune but I want to have good stuff. I could have gone with HF equipment and probably be fine but this is my curse… I always upsell myself to make sure I get something that I can grow into.
If you could take just a moment to give me a gut check on where I think I need to go with this: I buy a bolt on kit from the above mentioned, then buy the motor / controller kits (of which I haven’t researched as far as I feel these are more universal and could go on Grizzly’s, HF’s, PM’s but then… is there also a communication board or is this typically included with these kits? Then the software. Do I need both the software to run the machine and a software to design the part? I’m not asking you to go in great detail about these questions as I will do the research, but it sure would be nice if someone could tell me if I am considering all the right things so I don’t find after all this, I missed the ‘whatchamacallit’ that is required and I have to spend another $2,000 on it! I see Acorn, Fusion360, Mach4 software out there and not sure if I need just one or a combination of them. I am currently very fluent in Google Sketchup (don’t laugh, its free and I am just playing around) and was wondering if this could export files to the actual machine software. Again, not asking you to research or write a paper on this for me, but if you just happen to know…
What I see right now is the machine (+- with shipping and stand) at $2200, conversion kit at $800, electronics at $400 (this I may be off on, haven’t spent a lot of time there), software at $200. So I can get into this at $3600. Now I have to compare this to a ready made unit (saw one on ebay) for around $4k (so maybe I am in the ballpark with what I think I need). The problem with that ready assembled unit is, I don’t have control of which kits, electronics, software is used and I don’t get the experience of building it (also will play with it in manual for a couple months before I install the conversions, although I do want to go ahead and buy everything now). One other option is, build my own conversion kit; but I’m not going to undertake that now; perhaps on my next machine! I realize all the accessories, bits, holders, vice etc... are on top of the aforementioned costs.
I will cut this short (LOL) although I have so many more thoughts and questions; I was just hoping perhaps some hobbyist (or perhaps a professional) that loves this stuff and doesn’t mind enthusiastically helping someone trying to get into this fun field would chime in! Again, I think I prefer the PM machine but that Grizzly has so much more on the internet about it that I feel safe with it and am just hoping the PM machine has as much available out there.


Thanks so much for your time already in just reading this.

 

[Cadillac STS]

I would lean heavily on getting a mill that has a bolt on ball screw kit available. Maybe take some time and email those places that make the kits and get questions answered.

Mach 4 with a good usb motion controller is a nice way to go. There is other machine control software though.

You will need software to draw your parts and produce the G code to run on your machine. Autodesk Fusion 360 is great and it is free. Download the demo and when the demo ends let it know you are not using it to make money and you can keep using it free. I think they say if you earn over $100,000 per year then you need to buy it. Fusion 360 has a mode to generate 3D printer code too so if you know the software you could do 3D printing later and not have to learn new software.

 

[Boswell]

Welcome to the forum. There have been many threads on this forum on this same subject. spend some time searching and you will find a few. PM . has some solid machines and a loyal following. (I have a PM45M-CNC). I use Mach3 for the control software and the Ethernet Smoothstepper motion control board (it will work with Mach4 also). As Cadillac said there are many ways to go here. There are some very smart and experienced people here so this is the right place to ask questions.

 

[bakrch]

It is quite an undertaking that everybody seems to do a bit differently.

I suggest checking out @macardoso and @shooter123456 as they have some great build threads.

Personally, I went with ProCutCNC. Happy with the machine, but they just grab the parts from Automation Technology (or have reverse engineered what is sold there) and blindly throw them together. You would definitely have to tear it apart and rebuild it correctly, so it is quite a waste dealing with them.

The Arizona Video dude is pretty good, but NOT good with following through on how expectations are initially set. Never heard a complaint about his design or quality, so if you are okay with waiting an undetermined amount of time you will undoubtedly get a nice setup from him.

I learned on here the other day that PM actually sells CNC mills, if I had to do it over again that would surely be the desired route. I needed to make parts though and wasn't so much interested in the building part of it right away.

As mentioned already, Fusion 360 startup license is a MUST. Lars Christensen's youtube channel is a bit dated as software updates have changed the interface since then, but still quite the invaluable learning resource.

Mach 4 sounds like a good option. I grabbed Mach 3 to get me started, but eventually will switch over to the industrial Mach 4 as it supports Custom Macro B.

 

[shooter123456]

Feel free to have a look at my thread on my PM-25 CNC here: https://www.hobby-machinist.com/threads/new-pm-25mv-mill.65939/

To answer a few of your questions:

For electronics, decide if you want to go stepper or servo. Steppers work fine, servos are better (with a price to match). I have a bunch of prices listed, but inexpensive steppers and drivers cost me $258. My 3 clearpath servos and power supply cost me $1,232, then roughly $100 more for the cables. The steppers worked fine, but the servos are faster, quite, smoother, more reliable, and more precise.

The way I went for controlling the machine is LinuxCNC and an inexpensive breakout board. I have had 3 of these (https://www.omc-stepperonline.com/5...ard-interface-mach3-cnc-router-kit-st-v2.html) type of board and have had relatively few issues. I did short out one somehow trying to wire the spindle control (it also trashed my computer and tripped the circuit breaker, so I am confident it was my fault, not a board malfunction). LinuxCNC is free, easy to use, and has pretty low computing requirements. The computer I use at the moment is a 10 year old dell something or other that was $50 on craigslist. I have no complaints about its performance.

You do need software to run the machine as well as software to design your parts. I use Fusion360, which is both CAD/CAM software, and again is free for hobbyists. Your CAD software is for 3D modeling to design your part, and your CAM software is used to specify how you want to machine the part. If that doesn't make sense, you will input your tool information, speeds and feeds, select a machining strategy, and it will generate a toolpath. Once you are satisfied with the part and the toolpaths, you "post" the toolpaths and it outputs a G-code file that your machine will understand. G code if you aren't familiar just says "Move the X axis here while moving the Y axis here at this speed. Then move the Z axis here at this speed. Then..." You get the picture.

Of the softwares you mention, Acorn and Mach4 are machine controllers (same function as LinuxCNC mentioned above). You will need a CAD/CAM software and a machine controller software.

I would also strongly consider building your conversion kit. I made mine with no plans from others, and it really isn't that tough. I used my X2 CNC to help with some of the parts, but none would be prohibitively difficult to machine manually. The cost savings is pretty significant. If you estimate $300 for ballscrews, $30 for bearings, and $15 for couplers, you are at $455 savings over an $800 ready made kit. It might not look as nice, but it will function identically, and you can always redesign and rebuild once it is CNCd if you want to.

My cost estimate would be:
Steppers and drivers: $258
Power Supply: $50
Breakout board: $10
Ballscrews: $300
Bearings: $30
Couplers: $15
Raw stock: $50
LinuxCNC: $LOL its free
Fusion360: See above
Control computer: $50ish
Misc connectors and wires: $30
Mill: $2086 shipped to your door (with stand, though I didn't buy the stand)
Total: $2,879 (Roughly $700 less than your estimate)

Also, regarding the PM-25 vs the G0704, the PM-25 is a no brainer. It looks like the cost difference is now $350 shipped, but the PM-25 has:
-Factory belt drive (Quieter, easier to jack the speed up, less maintenance)
-Brushless motor (Quieter, more reliable, better low range torque)
-Better column mount (The PM-25 base extends further back and the column is bolted to it from the top. The G0704 has a shorter base and the column bolts to base from the back. Not hard to tell which is better once it is pointed out)
-Slightly heavier (Seems the gap has closed a little, listed as 10 lbs difference now, used to be closer to 40)
-Precision Matthews warranty. This alone is worth the extra $350. 3 years vs 1 year is a huge difference, and Precision Matthews support is incredible. I burned out the motor on my PM lathe, they walked me through troubleshooting to identify the error, and a new motor was on my front porch 2-3 days later. They covered cost of shipping and the cost of the motor. Their response time is also excellent (usually under an hour) and they have even responded to emails on weekends.

I hope that helps. Let me know if you have any questions!

 

[macardoso]

Hi Nrpdyer!

Welcome to the forum. There is so much depth to the whole "build your own CNC mill" that is can feel very overwhelming at first. If I can offer a piece of advice based on something I struggle with, try to focus on the essentials until you have a machine up and running. I can spend so much time thinking about add ons and accessories that it is easy to lose track of the main project!

I bought a Grizzly G0704 in 2013 for $1200 shipped. The price has certainly gone up since then and I would agree with the above advice to purchase your machine from Precision Matthews. I don't personally own any of their equipment, but I have heard nothing but good things.

Here is a link to my build log (https://www.hobby-machinist.com/threads/g0704-cnc-ac-servo-rebuild-picture-heavy.76222/ ). You have to understand that when I started, I did everything about as cheap as I could at the time and it really worked quite well. This most recent upgrade is massively overkill for this machine and I was mostly looking for an engineering project.

Everything below is my personal opinion only, compare my thoughts with others and choose what is best for you. None of these are in any particular order.

Control Software: I started off my time with CNC running Mach 3 and just recently paid to upgrade to Mach 4. I won't go into details of Mach 3 since it really shouldn't be used on new builds, but I have to say I am very impressed by Mach 4. The basic setup to get your machine up and running is quite easy, the layout is pretty professional, and there is a ton of customization capability to make your system do what you need it to. The forums are well traveled and the New Fangled Solutions staff are often answering questions directly on there. I have never used LinuxCNC so I cannot compare, but I wouldn't hesitate to recommend Mach 4.

Motion Controller: Perhaps one of the most critical selections you will need to make is the motion controller. This board sits between your computer and motor drives and is responsible for generating the motor command pulses and handling all the I/O. In the early days of hobby CNC this was done through the parallel port, but now it is either USB or Ethernet. Based on my experience, I would highly recommend the Ethernet Smoothstepper from Warp 9 TD. It is the fastest non-commercial board that I know of, and it handles something like 50 I/O points so you can build a rather complicated system around it (or give yourself room to grow). The board itself just works, no questions asked. No settings or anything complicated to make it happen. The biggest selling point is that Warp 9 TD runs a private forum where Andy, one of their staff, answers nearly any question you can imagine. I've learned more about Mach 4 on their forum than on the Mach 4 forum itself. The service is amazing.

Steppers vs. Servos: This one is really a matter of budget. Servos are better, no questions asked, but 98% of the hobby world uses steppers and they get stuff done no problem. I was fortunate to get some legacy servo hardware from my day job, but I probably would have stuck with steppers otherwise. Clearpath and DMM technology seem to be the big players in the hobby servo market today, and there are hundreds of options for steppers. I bought from StepperOnline (they're very cheap and sell complete kits) and Gecko Drive is at the high end of things for the hobby market.

Kit of Parts vs. Plans: I bought the Hossmachine plans back in 2013 to convert my mill (there really weren't kits available at the time). It worked very well, but I wasted almost a year trying to build the kit without access to equipment beyond the out of the box G0704. If you have the money, I would recommend buying a complete kit. If you have time and access to machine tools (and know how to use them well enough to make the kit), making your own can be a learning experience.

Building your CNC vs. Buying Turnkey: Think about what you're going to use this for. I had a buddy who built RC race cars. His machines enabled his other hobby so it made sense for him to buy them ready to use. For me, I am happiest when I am designing and building, so at least half the value of the machine to me was getting to put it together and be proud of what I've built. I sometimes struggle to come up with projects that aren't parts for the machine

Thoughts about Electronics: I think a lot of people forget or underestimate the electronics side of the build (cost and time). Even if you're buying a kit of parts, you'll still need to put them together and put them in a box. Having done both, you'll be much happier having your controls inside a professional electrical enclosure rather than a tupperware container. There are tons of surplus enclosures so I'd budget for one. My first real enclosure was 24x24x6 and my latest one is 24x36x8 (I have a LOT of stuff in the enclosure). Think about getting larger than you need so you have room to grow.

Software: I use Autodesk Inventor and MasterCam but most everyone nowadays uses Fusion 360. I personally didn't love it, but that's because I am so familiar with my workflow. There is a great community around Fusion 360 and tons of training content. This will allow you to design in 3D and convert to machine code (G code) in the same piece of software.

Tooling: Since it sounds like you're just starting out, plan on having plenty of tooling costs. You don't need much to get going but it is endless. When I started, I went wide eyed when I saw a family friend's home machine shop (retired tool and die maker). There was 20 of every kind of tool you could imagine. When I asked him how he afforded it, he explained each piece had been slowly acquired over a 50 year career. I always remember that and only get the one thing I need at a time. Maybe when I am 70 I will have a shop like his.

This is all an amazing learning experience and a great reason to connect with an incredibly knowledgeable and friendly community. I would be happy to continue to answer any questions you might have no matter how large or small.

-Mike

 

[shooter123456]

I sometimes struggle to come up with projects that aren't parts for the machine

I thought that was just me...

 

[matthewsx]

I'll jump in here even though my project is far from completed.

I do agree with first deciding what your goals are, if you just want to make parts then buying a ready made machine is probably a good idea. I decided to build an entire machine, not just convert one since I didn't have a machine already and my budget is very tight. There are things I expect to come back and bite me but I value the experience more than ultimately having a super precise machine.

If you want the experience it's probably a good idea to build as much as possible yourself. From reading about other's builds it seems like you're likely to have to modify/change components anyway, plus if you do it yourself you won't have the frustrations of waiting for someone else to provide the parts you need. Although kits can be great most of them seem to have components you can buy yourself cheaper and the rest is stuff you can build with the mill.

I'm planning on using LinuxCNC which I already have talking to my free stepper motors (from another forum member) through a $15 parallel card in my old computer, a $20 5 axis controller and $10 stepper drivers. I'll be using FreeCAD to design parts and generate g-code, so definitely going as free and opensource as possible with recycled and repurposed components wherever possible.

Even though I haven't started making chips yet I've already achieved several of my goals and learned a lot of things that will help me in future projects. It also seems like older CNC equipment with outdated controls is available pretty cheap so I can see retrofitting something more capable in the future as I learn more.

So, welcome to the forum there's lots experience and help on here. The road you're starting on has lots of different paths (pun intended) you can follow and plenty of opportunity to create your own as well.

Cheers,

John

 

[Nrpdyer]

Thanks for the valuable input so far. I did order the Precision Matthews 25mv today!!! So now the fun begins (well, when it gets here presumably in a few weeks...)

So on the electronics side, I think I'm understanding the flow a bit better...

1) Concept to 3D (CAD via Fusion 360)
2) 3D to G-code (CAM also via Fusion 360) which knows the part geometry and the tooling geometry and some variables about speeds, cut depths etc. entered by the user to develop 'cut plans' or 'tool paths' in the form of G-code.
3) G-code to motion control software (Mach 4). This software converts G-code to commands for the hardware. This software provides limit switch protections and knows a lot more about the machine itself (axis sizes etc...), and displays machine status. On this, are there compatibility concerns or drivers? Does this software have all of the jog and manual movement controls?
4) Mach 4 to the motion controller. These seem to work pretty closely together as if the controller (maybe a Warp 9) is the hardware interface between the software and the motors and sensors. With this, I assume compatibility must be checked. It seems many controllers that I have seen are specifically developed for certain programs (such as Mach4). Also it seems there are drivers which must be used for the software to talk to the hardware.
5) Motion controller to stepper drivers (unless they are on-board with the motor). Controller provides the low power commands to the drive and the drive provides the power to the motors. Am I missing a breakout board here or is that commonly integral to the controller, or one in the same?

Where would a pendant (MPG) plug into this system and what is your opinion on the necessity of this?

And of course cabling, power supplies, limit switches, cabinet and computer. On the computer side, ethernet sounds like the way to go nowadays but my laptop has no port. I could use a USB to RJ45 converter but then have no electrical isolation (surely they make a converter with this isolation as part of it). This or go wireless? Or, converter with network cable plugged into router which would then provide isolation.

All of the brands of software / equipment above are just examples and I understand there are viable options out there. I also made some 'statements' which are actually just assumptions at this point so please correct me if I am wrong.

Maybe it's just me but I haven't found a good tutorial which puts all these pieces of the puzzle together in one place. Perhaps when I succeed, I will do that!

Thanks again, I'm having a blast already and don't even have a machine!

I sometimes struggle to come up with projects that aren't parts for the machine

I'm afraid that's going to be me too.

 

[hman]

I'm just getting started in CNC myself. Let me add what amounts to step 2.5 - be sure to load the Mach 4 post processor into Fusion! Think of G-code as a language with many dialects. The post processor (or simply "post") translates the basic language into the correct dialect.

As for the pendant ... I'm running Centroid on my mill. The pendant plugs into a USB port on the computer that runs Centroid. I use it on every job for the following:
(A) Measure/set the height of each tool, i.e., populate the tool offset library/table This is usually done by using a "taster" or similar contact probe (that plugs into the Centroid board), but it can also be done by slowly and carefully lowering each tool down to a reference surface, using -Z moves controlled by the pendant, until it makes contact.
(B) Set the X, Y, and Z locations on the work piece. I do X and Y by placing a thin rod or pointer in the chuck, lowering Z to near contact, and traversing the table to where the point is just above the position of the X=0 and Y=0 that were defined for the part in your steps 1 or 2. Then home the spindle, mount one of the tools defined in (A), and lower Z until its end is at the level you've defined as Z=0.

You don't absolutely NEED a pendant. The Centroid screen includes controls that allow me to move X, Y and Z with mouse clicks. But the pendant allows me to focus my eyes on the tool and the part while moving things around, rather than constantly shifting my attention back and forth between the screen and the work. I'm sure Mach 4 has a similar feature.

Regarding Ethernet and your proposed work-arounds ... just be aware that every "layer" of adapters and/or converters has the potential to add time delays. So be cautious! I bought my (used) mill as a "turnkey" system from Marty Escarcege, who's the Arizona rep for Centroid and who's made some of their instructional videos. So I know it was built right and is rock solid. It includes a Lenovo mini-pc (about the size of a small hardback book) with an Ethernet port. Never had any issues with timing.