Jamie's PM-30 build. Clear Path. Acorn. Arizona. Enclosure.

Jamie_Murray

Registered
Registered
Joined
Mar 6, 2022
Messages
23
Hello all. First and foremost thank you to the admins and contributors for creating this repository of information. I've seen the other threads on this but I'm looking for the most up to date information as it seems like there have been a couple of disruptive technologies implemented since my last foray with the G0704. I've spent a decade looking into subtractive and reading forums just like this one. For every one person making a post like this, there are likely hundreds who have the same question. The days of paralysis by analysis are over for me however and I'm ready to make the leap!

My name is Jamie and I am looking into building a CNC machine. I purchased a G0704 in 2014 with the intention of converting it to CNC, but then joined the military shortly thereafter and made the decision to sell it with the plan of coming back to it once I get out. Fast forward to today and I am ready to make the leap.

I'm currently using my G.I. bill benefits towards the eventual goal of a graduate degree in mechanical engineering. My intention is to build a machine which will allow me to grow in the short to medium term with a bigger and better piece of equipment on the time horizon of ~2025-2028. In an effort to hedge against the rapid onset of technological innovation in regards to metallic additive I've made the decision to go with a smaller hobby grade mill. This decision has also been made as my involvement with the local Formula SAE team and colleges in the area would likely allow me access to industrial grade machines for the rare prototype which requires a level of tolerance that optimization cannot provide on my set up.

The Tormach 770MX and 1100MX were looked at, but for the price I'd rather just get a Haas Mini Mill. While I do have the capital to make that purchase I beleive it would be more prudent for me to start with something a bit more manageable to get my feet wet, then make the decision to move to a VF series in a few years while monitoring barrier of entry to additive. The workspace I have for the mill also needs to be taken into consideration. I have a 2.5 car garage but there are many motorcycles and a car which stay there so the space I have to place a machine is approximately 66"L X 46" D X 117" H with an 82" garage door height.

The education that I received while planning my G0704 build as well as a small course I took at ORNL's MDF on Haas equipment was invaluable and has given me a much clearer picture of what I need to do and where I need to go. With that being said, a smart man learns from his mistakes while a wise man learns from the mistakes of others. While I think it isn't necessarily a direct translation, the jist is I'm looking for hindsight from those who have been there and done that. The unknown unknowns so to speak.

Current plan:
PM-25 or PM-30
clearpath servos
Acorn
one shot oiler
flood coolant
power draw bar
After looking at and considering the ProCut enclosure I'm looking into making my own to see what type of rigidity I can get with a column brace.
Band saw
some way for touch off...I've seen converted Renishaw probing as well as cheaper new options
a more quiet air compressor than my loud standing craftsman


I have associated mechanics tools from motorcycle racing and most normal things you would find in a motorcycle shop but my current home manufacturing capability is almost non-existent with a Dremel and files being the primary means of subtractive. I have access to multiple 3D printers at the college if something low strength needs to be produced, but I don't imagine it will be a significant help. The ProCut CNC enclosure looks to be a decent piece of kit. Are there other options out there? I don't mind doing it myself if there is a modular design that allows me to bolt it together but both my access to and knowledge of welding is insufficient at this moment to take that on myself. Fit and finish is a tiny bit important so while it is completely functional, making the enclosure out of wood is not something that I'm interested based off what I've seen so far. But maybe there's a design that is slick and not too hard to do that I don't know about! Teach me please.

So far as I can tell Acorn seems like a superior option to the tried and true Mach 3 in terms of room for overhead development and expandability. Once I possess equipment which can make equipment then I'm sure I'll start to do gradual improvements here and there (Power draw bar, maybe dual belt depending on motor size choice, eventually an ATC). The key is to get limited manufacturing capability ASAP in my current shop which will allow me to grow and justify my plans for building a shop.

As far as expectations are concerned, I'm keeping them tempered I beleive. I should be able to spend enough time taking measurements for software screw compensation to make a machine which is reasonably positionally accurate with low backlash due to the double nut ballscrews. Rigidity will likely be my key limiting factor once motor size/speed is sufficient, but if I go slow and understand the material properties of my work piece then despite the price tag, I should still be able to produce somewhat accurate prototypes that will allow me to grow as an engineer. Then once I'm ready to take the next step for serious production of my designs and starting a business I'll get a bit more serious machine.


SOOOOOOO after all that; what says ye? PM-25 with a Procut CNC enclosure, clearpath servos, acorn, and all the various other subsystems? This would keep me on 115v with a normal wall outlet so one less thing to do for home electrical. Or perhaps an unknown unknown? Tell me what you wish you would have done please!
 
Last edited:
So it may or may not be too late to make the PM-25 vs PM-30 decision. Dave from Arizonacnc called me today and we had a lengthy chat about a number of things. I was leaning 80 percent towards the PM-30 over the 25 already, but the chat with Dave confirmed that so after seeing there they were listed as in stock after a lengthy backorder I just decided that now is the time and pulled the trigger!!!!

It's probably not as big of a deal to most others, but this is big for me. I had done over a year of weighing options in my early twenties on the G0704 before pulling the trigger and having life change circumstances on me with the military. So finally being in a position where I can create my first machine that will start me down the makers path is very exciting.
 
That is awesome! Congrats on the new mill and welcome to the best machining forum on the web!
 
If you are going with an Arizona CNC kit, I am sure you will be very happy with it. Dave is great to work with.
 
That is awesome! Congrats on the new mill and welcome to the best machining forum on the web!
Thank you very much. To make good news better, I just discovered a video uploaded just yesterday by James at Clough42 on YouTube where he has went to great lengths to make as modular a control package as possible. The design is impressively mature and this dude rocks.
 
If you are going with an Arizona CNC kit, I am sure you will be very happy with it. Dave is great to work with.
I am almost certain that I will be going with the Arizona CNC kit. My conversation with Dave today confirmed that he is a wealth of knowledge and that if I have issues in the future he could most likely be counted on to help troubleshoot the aspiring machinist.
 
Did a little work on the rough draft for a mill stand. It's been a while since I opened Fusion and I remembered how to do some things halfway though making this, so let's look more at concept than execution here. Anyone see any glaring issues? My though process is to make a 4" box steel frame to provide as much rigidity to the small base of the PM-30 as possible. Then the column support along with the appropriate shimstack on either side for tramming and squaring purposes?

There are two schools of thought that are immediately apparent to this untrained monkey. The obvious first choice is to place as little load on the machine as possible while still transmitting energy for attenuation. I think this can be done with somewhat accurate welding and shimstack to make up the difference when installing the base and column onto the stand. I haven't decided if I'm going to bolt the stand to the floor or not. It seems like in theory this would provide a better path for energy dissipation? I would imagine that a set of large leveling pads would be a more appropriate choice and is likely the direction I will take.

The second method that I briefly considered was to store mechanical strain into the column with fixed rate attach points and resurfacing of ways for parallelism. This would reduce the overall strength of the column and attached base as a unit but would have the benefit of requiring a higher force to flex the assembly as the static state is already X% into the stress/strain curve. While the precision to do this may be feasible with enough time, the added complexities when simply considering thermal effects already makes it unfeasible for me.

Keep it simple stupid. Fill the base and column with as much epoxy sand as you can squeeze in, build a somewhat heavy rigid base and try to not twist anything when we clamp it all down. Any other ideas?

1646686236997.png
 
Good news. A friend of mine has the capability to do the enclosure. (And being a machinist with a shop himself, I beleive he will do a good job). I wish that I had the equipment/space/time to do this part of the build myself, but the unfortunate reality of life is that sometimes you've got to outsource to keep the ball rolling. I'll be able to make cool things that I think of once the machine is built, and that's the real goal here, right?

This means I can start actually thinking and working on enclosure design a little more seriously now. I know I want sliding doors with impact/scratch resistant windows which I have a source for locally. I also think I want at least one, if not both side windows on the enclosure to have the ability to open for long work pieces. I'll likely just run some diffused LED strips inside for lighting. I'm not sure if I'm going to encapsulate the touch screen control into the enclosure as a flush mount or if I'll run a mounting arm. Maybe a mixture of both...

Stainless, or painted for my enclosure finish.....hmmmmm? What is interested to note is that when I started this thought process my intention was to go pretty mild; now in my mind I'm considering different paint schemes for my enclosure (a two tone design with a diagonal split perhaps). LOL.

I also spoke with Tom over at Teknic who not only provided me with motor recommendations based off of my predicted use case but also gave me some new videos to watch that will get me up to speed on what I should know moving forward. Good dude!

Going to start work on the electronics list/package soon. I'm sure I'll be leaning heavily on the internet again.
 
I realized that I "needed" to remodel the office and build a decent PC to serve as the heart of development/productivity/leisure. Then finals came and I dropped everything to hold on to the A's. Taking the summer off to do some projects as well as an internship so this is back on the front burner now.

After speaking with some friends who are smarter than I; I've decided to scrap the column bracing design due to differential material growth characteristics. Not sure if I'm going to weld or bolt a frame together for it yet. Trying to keep mistakes to a minimum, but paralysis by analysis is also a bad thing...

Here's the PC build :)
 

Attachments

  • 20220511_150503.jpg
    20220511_150503.jpg
    95.1 KB · Views: 160
Back
Top