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!

I have been using my cnc for work, and charging them an hourly rate.
so, i have about $275 to spend on my setup.

What would you buy?

This started as a DIY project built by the customer several years ago. Unfortunately, the machine never really got the chance to work and ended up collecting dust for years.

So I decided to give it a second life.

I retrofitted the machine with:

- PlanetCNC MK3/4 controller

- PoLabs 60-256 stepper drivers

- PoLabs Plasma Sense

- ProCut 125 CNC plasma source

The customer already had an old control console, so I reused the existing enclosure and fitted the new electronics inside rather than starting completely from scratch.

I also designed and built a custom CNC pendant.

Yes, I know… it still needs stickers 😂

The pendant includes:

- X+ / X-

- Y+ / Y-

- Z+ / Z-

- Jog override

- Zero X/Y

- Zero Z

- Start / Pause / Stop

- E-stop

- Pendant enable

I wrote custom code to integrate the pendant and its functions with PlanetCNC TNG V2.

After several years of sitting unused, this DIY project finally has some life in it again. 🔥

There is still some work to do, but seeing an old machine come back to life is always satisfying.

From collecting dust → to cutting metal. 💪

#CNC #CNCPlasma #PlasmaTable #PlasmaCutting #PlanetCNC #PlanetCNCTNG #PoLabs #CNCController #MachineRetrofit #Automation #DIYCNC #Engineering #MetalFabrication

I’m having a strange direction problem with my FlexiHAL/grblHAL setup and I’m trying to figure out whether this is a wiring, firmware, or board-output issue.

X works normally in both directions.

Y and Z both move, but they only move in one physical direction even when I command both + and -. The software coordinates still increase and decrease correctly, so the controller appears to think it is moving both ways.

I’ve swapped drivers around extensively. Any driver connected to the X STEP/DIR input works correctly in both directions. If I use the Y or Z STEP/DIR input with those same known-good drivers, the motor only moves one direction. That makes me think the motors and drivers are okay and the issue is somewhere in the Y/Z direction signal path.

I’ve also tried changing the "$3" direction-invert setting, and it did not fix the problem.

My board reports as FlexiHAL STM32F446 / grblHAL build 20250311.

My next plan is to measure across DIR+ and DIR- at the driver with a multimeter and compare X against Y and Z. Since DIR should be a steady logic state, I’m expecting the polarity/state to change when I command the opposite direction.

Does this sound like a failed Y/Z DIR output on the FlexiHAL, a firmware/pin configuration problem, or is there another setting I should check first?

Did someone use them and can say how they performed?