I have a lot of cabinet building in my future, so I’m looking into building a large-format CNC router that can handle full sheets of plywood. I’m thinking of a metal construction (square tubing and ~4 mm laser-cut plates) similar in design concept to this CNC plasma cutter: https://www.youtube.com/watch?v=2jZwh6mvMhQ

What I’m trying to figure out is the motion system for the X and Y axes, as well as a target feed rate. So, here is my idea:

I already have, and want to reuse (from a failed project from my high-school days):

- 2.2 kW water-cooled spindle with VFD

- 3x  23HS9442 NEMA 23 steppers(2.8 Nm), DM542A drivers at 36V

 According to https://cncshop.com/pages/calculating-feeds-and-speeds I figured that if I want to cut plywood with a two-flute, 6 mm bit, I need a feed rate of 5,000–6,000 mm/min. If I want to cut a pocket with a two-flute, 10 mm bit, I need 14,000–16,000 mm/min. 

For a CNC of this size and application, I’m considering an HTD5M, 15 mm or 20 mm timing belt, with a pulley coupled to a planetary gearbox. 

Even though I cannot find a datasheet for my stepper motors, after looking at torque curves for other similar-sized steppers, I concluded that 250 rpm is the speed at which the torque starts to drop off.

 With all this out of the way, let me explain my calculations. The first table shows the output torque, calculated as follows: 

Output torque = stepper rated holding torque × fraction of holding torque at operating speed × gearbox ratio × gearbox efficiency 

I have assumed a fraction of 0.7 for the running torque and a gearbox efficiency of 0.9.

For example, for a 3:1 gearbox: 

2.8 N·m × 0.7 × 3 × 0.9 = 5.292 N·m 

The second table shows the axis linear backlash based on the gearbox backlash and the pulley pitch diameter:

Backlash = pitch diameter × pi × (gearbox backlash / 360) 

For an 18-tooth pulley with a 28.65 mm pitch diameter and 0.5° of gearbox backlash: 

28.65 mm × 3.14 × (0.5 / 360) = 0.125 mm 

The third table shows the feed rate, in mm/min, for a stepper running at 250 rpm, depending on the gearbox ratio and the number of pulley teeth: 

Feed rate = (number of teeth × tooth spacing / gearbox ratio) × stepper rpm 

For an 18-tooth pulley and a 3:1 gearbox: 

(18 × 5 / 3) × 250 = 7,500 mm/min 

The final table—which I will probably get some hate for—is the equivalent mass being pulled on the gantry in kilograms. The gantry has two stepper motors. I calculated this to get some feeling for the force generated by the motors when moving the gantry: 

Equivalent mass = torque / pulley radius / gravitational acceleration × 2 

For a 24-tooth pulley and a 3:1 gearbox: 

5.292 / (0.0191 * 9.8) * 2 =56.5445 Kg 

Okay, the math session is over. What do you think? Do you agree with the logic? What combination of pulley size and gearbox ratio would you choose? A 28T pully and 3:1gearbox gives a speed of 11666mm/min and a “oomph” equivalent to 48.4Kg – I think that is a good compromise. 

PS: I will be posting this in multiple CNC groups.

What are you using, and what are your typical projects and materials? I'm thinking about getting a water cooled spindle because air cooled variants are often not suitable for flood or spray cooling of the workpiece. Although, I don't really like the additional hassle of a water cooling loop.

Hi everyone, im in the process of building something i can use to cut speaker panels but do not have to space for an 8x4' table cnc.

Ive been interested in the compass cnc but it had been halted due to copyright i believe. I was wondering if anyone had a copy if the BOM and assembly instructions. I have requested acees to the original files but to no avail.

Id also be interested in alternative options for handheld router cncs if there are any! Appreciate any help.

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I'm putting together a parts list for my second cnc machine, a CO2 laser cutter, and I cannot get information on choosing a proper power supply. With my first everyone just told me one to get and wouldn't tell me how to determine it for myself. Now google and AI refuse to give me what I ask for cause it can't determine the difference between the laser power supply and the system power supply, ie. the co2 laser power supply is plugged into the system power, and for some reason the open builds site is down. Current parts:

-Cloudray cr50 laser tube

-Cloudray 80W laser power supply

-2 DM542T Stepper Drivers

-3 Nema 17

Chiller and controller will be independently powered. Might be looking to power an inline fume extractor and lights off of it as well. Looking for something like a formula that I can add parts to. Any help would be appreciated.

I have a very small space and like the idea of a cnc plasma small enough to stick to the sheet and then hang on the wall.

I have experience with other small CNC, built my first delta 3d printer from scratch and currently run FDM and resin printers and a K40 laser so the JD's Garage build is within my skills.

Thing is, while the JDG YouTube channel has a hundred videos, I don't see anybody else saying they built one, they use one, they love it. Seems like there should be a whole community, maybe even a subreddit?

I see a lot of "my gantry is noisy / rough / inaccurate" threads, and the hardest part is usually not fixing the problem — it's figuring out which assembly actually has the problem. The rail and the belt are mechanically in series, so a symptom in either one shows up at the toolhead.

The method I use is a disconnect test, done in order. It takes about ten minutes and needs no special tools.

Step 1 — both belts off. Disconnect the belts at the carriage and move the toolhead along the rail by hand. If it glides freely now but was rough before, the rails were never your problem. You were fighting belt tension, an idler bearing, or pulley concentricity.

Step 2 — one belt at a time. If it is still rough with both belts off, reattach one belt and test again. Whichever belt reintroduces the roughness points at that drive path. On a corexy or a gantry with shared motion, a single over-preloaded carriage or a rail not sitting flat on its extrusion will drag the entire path, so this step is what isolates it.

Step 3 — the one-finger gauge. You should be able to push the carriage along a properly preloaded rail with one finger at a steady speed. If you have to lean into it, something is preloaded. The usual culprits are the carriage bottoming on an endstop, toolhead plate bolts over-torqued and pulling the rail off its reference edge, or the rail seated against paint or a burr.

Step 4 — position dependence. Move the carriage slowly across the full travel and note whether the roughness appears at the same place every time. Repeatable roughness at one position means the rail raceway has damage there. Roughness that tracks with the carriage regardless of position means the carriage is the problem.

The reason this ordering matters: I have caught myself re-tensioning belts when the rail was the twisted one, and I have replaced parts that were fine. Doing the cheap disambiguation first avoids both.

Disclosure: I work for a linear motion manufacturer, posting here as a personal account, not representing the company.

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i want to make a cnc machine not for cutting but for other purpose but it has the same structure as the cutting machine with some changes, i wanted to start in the design, but i dont which program should i use, i dont know much about mechanical designing but i have a little knowledge on 3d modeling, So i will need some tutorials online (free), so what do u guys think is better and easier?

Running a 3018 clone that I've upgraded piece by piece over the last year (better rails, a proper spindle mount, stiffer Z plate). Aluminum cuts had always been a little rough but lately it got bad enough that I was getting visible chatter marks even at conservative feeds and speeds, like 400mm/min at 10000rpm with a 2 flute 3mm endmill.

First thing I did was tear into the whole machine thinking it was rigidity. Reseated the gantry, checked every bolt, shimmed the Y rails, even swapped the stepper drivers because I had a spare set. None of it made a dent. Cuts were still leaving that washboard texture on the walls.

Out of pure frustration I pulled the collet and endmill and just eyeballed them under a loupe. Collet had a tiny bit of gunk packed into the slots from months of cutting without ever cleaning it properly, and the runout when I checked with a cheap dial indicator was embarrassing, something like 0.08mm. Cleaned it out with isopropyl and an old toothbrush, swapped to a backup collet I had sitting around, and the next test cut was night and day. Smooth walls, consistent sound, no more screeching on the deeper passes.

Feels dumb in hindsight because runout is like the first thing people tell you to check, but when you're staring at a machine you built yourself it's easy to assume the problem is something you did wrong structurally rather than something as unglamorous as a dirty collet. Anyone else have a "should have checked this on day one" moment that cost way more time than it should have.

No matter what I set the spindle output to, after 20 to 30 seconds the spindle powers down. The board is powered by a 12v 5a PSU, the stepper motors don't stutter, the spindle power led behaves with the spindle, and setting the power to 0 and back to any power level restarts the clock.

The power is coming from the spindle screw terminal not the 2 pin or 3 pin connector ports. What gives?

Edit: should've clarified the tool is a needle cutter 2218 brushless DC motor, and the issue remains whether or not the tool is even connected. MKS DLC32 v2.1, makerbases shipped firmware 2.2.6 (unavailable in their repo)

I'd like to keep the screen control if I can, which grblhal and fluidnc may not support

SOLVED: seems like a safety feature. When flag indicating laser use (as opposed to spindle use) is true, there's a movement timeout. If the head is stationary for a few seconds the laser power is cut to prevent burning. By continuously providing movement inputs the tool power remains on. Unsure if laser flag off would behave differently.

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Hi everyone,

I'm currently working on a simple plasma CAM program, mainly aimed at making the workflow from DXF/design → toolpath → G-code as straightforward as possible.

The project is still in development and I'm looking for a few people who actually use plasma CNC machines to try it and give me some honest feedback.

It currently supports/post-processes for:

Mach3

LinuxCNC

GRBL

PlanetCNC TNG

I'm particularly interested in feedback about:

toolpath generation

lead-ins / lead-outs

kerf compensation

pierce settings

usability/workflow

G-code compatibility

anything that is annoying, missing or simply doesn't make sense

I'm not trying to sell anything at this point — I mainly need people to test it on different machines/controllers and tell me what works and what doesn't.

If you'd like to try it, feel free to send me a DM. I'll send you the test version and would really appreciate any feedback, good or bad.

Thanks!

One may need repairs, I'll ship on buyers expense. I used to have a good flair with GAFS.

well i have same garbage like forever ,,when prices on ebay was 600 ,when they start to use red usb card in these...

anyhow ,i upgrade her like million time ,,i lost count what i did to it ,and still make problems here any there due my idiotic idea red usb controler work thing,

so brand new virgin 6040z ,, which is easy way to upgrade it to run nice is question..

well first i suggest was additional clamp to spindle, axbb controler (will get one for me if i find how to reconnect from red one)

contact or proximity switch on all y x z

new bed ,i was lucky and have hands to 10mm thick stainless board ,so wonder will 8mm normal steel work fine for bed ?

i use on z line (x + z double ) hiwin linear rails for z and x lines ,to stiffen it up a bit ,can he use some normal linear rails to easy up on his pocket (he still work on eng degree) and which ones ?

i switch from all cables to shielded ones ,ground it all up ,plus braided spindle ones in one to not touch others, drivers to dm542 (i switch all steppers to closed loop ones and CL57T-V41 ,to tell him to do same ? ) or Nema 23 Closed Loop Motor 1.2Nm(+ 169.93oz with cl57t driver ?

i got new plastic box for all el parts i added couple coolling fans and longer cables to tuck all under table where pc is ,mpg and z-tool and keyboard only on top ..

anything else i miss ?

well thanks for all advices

he is on lower end of budget ,but have looad of ideas ,,mats will be using are brass, alu ,even wood

thanks

Hey all of you! I'm planning a possible cnc build out of aluminium extrusions (I KNOW STEEL IS BETTER) and stumbled upon the Vallder X-Axis Extrusion ( https://vallder.com/de/product/cnc-x-axis-heavy-alu-profile-235x125/ ). It seems like a perfect fit for my small rigid machine project aimed at machining aluminium, carbon and maybe some steel... But as I looked at the measurements on the extrusion slots, I really wondered how one would go about mounting this to conventional 80x80mm extrusions? Would I need custom machined aluminium angles or something (The distances are like 47.5 and 65 mm or something crazy like this)? Anybody done this before? Thanks!

Has anyone tried implementing force feedback controls for a CNC machine?
I'm building a CNC lathe but want to use it mostly as a manual machine and I feel like it would be a lot more usable if the controls had some tactile feedback.
I got a solenoid clutch for a printer that can go from 0 friction to complete lockup at 12V (with a fairly smooth ramp between) and I was thinking I could just have the friction tied to the motor power (measured from the line inputs to the driver board).
Any reason this wouldn't work and has this been tried before?
I'm hoping it will get harder to turn the wheel as the depth of cut and resulting motor power increases giving you a feel for how the machine is performing.

Just completed the Metal cutter variant of PrintNC. Full build video can be found here:

https://www.youtube.com/watch?v=oM1bcv8IxZg

Happy to answer any questions!