Weird laser head movement problem

Design and or Build your Own Laser in part or Whole
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Weird laser head movement problem

Post by Elias Rautio »

Hello everybody!

I am building DIY 1500x1000mm 80w laser machine, and I'm having a weird problem on laser head movement. If I move laser head manually from controller screen arrows or when it is homing it moves normally. When head is homed and coming back to previous position it starts to move weird. It looks like it would lose signal from controller to driver multiple times over and over and the laser head is kind of "jumping" forward constantly accelerating and decelerating. Same problem happens when cutting or framing. It seems like when telling machine to move constantly forward ( moving manually or homing) it works good, but when it is told to move specific amount it starts misbehaving.

I think you need to see a video, explanation is a bit confusing:
https://drive.google.com/drive/folders/ ... sp=sharing

I had previously smaller generic chinese laser wich I used as a organ donor. I harvested Ruida rdc6442s-b(ec) controller and psu, 80w laser tube and psu from it and everything worked fine before wiring them to my new machine. Other parts I bought new (bigger closed loop stepper motors, drivers and psu for drivers etc).

I have checked motor and driver wirings many times, rewired with new wires, tried unplugging everything else from controller except drivers, I have tried different drivers and different stepper motors, I have tride open loop mode. Nothing seems to help. I am all out of ideas, no idea what's wrong.
Could it be some configuration error or software error I can't figure out? Any ideas what could be wrong?

I appreciate any help, I have been stuck over month on this and it's making me crazy!
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Gene Uselman
Posts: 2084
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: AKL1318-2
Laser Power: 130W & 80W Reci
Laser Bed Size: 51 x 71
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
Ruida Controller: RDC6445
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, Prusa i3 MK3S and Mini Prusa printers.
Windows Version: Win 10 Pro

Re: Weird laser head movement problem

Post by Gene Uselman »

I finally got the first vid to play but did not see anything really unusual. You are using the Vendor files from the donor machine and that would be my first place to examine. We have generic 'Rescue' files, I would choose one as similar to your current machine as possible [I don't know how common the upper left home position is- none of the machines I have worked on have had that config- be careful] and save the files you now have first. Gene
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BT48 Alpha Shopbot and 1300x1800 130W Laser

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Ray Wylie Hubbard
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Re: Weird laser head movement problem

Post by Elias Rautio »

I filmed 4k 60fps by mistake so file size is really big and preview takes a lot of time I see. I can take better video tomorrow.

Problem is better seen in the second video. In first video I show that movement is normal when moving manually from controller and problem is only seen short time after homing.
User avatar
Gene Uselman
Posts: 2084
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: AKL1318-2
Laser Power: 130W & 80W Reci
Laser Bed Size: 51 x 71
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
Ruida Controller: RDC6445
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, Prusa i3 MK3S and Mini Prusa printers.
Windows Version: Win 10 Pro

Re: Weird laser head movement problem

Post by Gene Uselman »

Just noticed you are in Finland... I grew up in a little German town in Minnesota, surrounded by little Finnish towns. Spent six years in the National Guard with a bunch of Finns, wild people... lots of fun.
If the Help and advice you received here was of VALUE...
Please consider making a donation to maintain the RDWORKSLAB Forum.

BT48 Alpha Shopbot and 1300x1800 130W Laser

The days that I keep my gratitude higher than
my expectations, Well, I have really good days.

Ray Wylie Hubbard
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Re: Weird laser head movement problem

Post by Elias Rautio »

I have heard there are lots of Finns in Minnesota. Finns are kinda their own breed :D

I tested vendor rescue files, it didn't help.

I added a new smaller file size video in the drive link. You can see it is homing correctly with one smooth movement but after that it starts misbehaving, accelerates and decelerates in middle of moves. Very weird problem and it is making my machine useless. I am really close of buying new controller but those are not cheap...
User avatar
Gene Uselman
Posts: 2084
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: AKL1318-2
Laser Power: 130W & 80W Reci
Laser Bed Size: 51 x 71
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
Ruida Controller: RDC6445
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, Prusa i3 MK3S and Mini Prusa printers.
Windows Version: Win 10 Pro

Re: Weird laser head movement problem

Post by Gene Uselman »

I have a couple I could loan you if you drop in tomorrow? I cannot read the speed screen on the controller readout- does that change when you are having the speed change problem? Just watched the third video- if you run that rectangle over and over, does it repeat the speed changes exactly?
If the Help and advice you received here was of VALUE...
Please consider making a donation to maintain the RDWORKSLAB Forum.

BT48 Alpha Shopbot and 1300x1800 130W Laser

The days that I keep my gratitude higher than
my expectations, Well, I have really good days.

Ray Wylie Hubbard
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Re: Weird laser head movement problem

Post by Elias Rautio »

Controller screen speed readout is staying same, but stepper drivers screen speed readouts changes when problem is occurring.

If I run that rectangle over and over it seems it is repeating speed changes exactly same spots
User avatar
Gene Uselman
Posts: 2084
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: AKL1318-2
Laser Power: 130W & 80W Reci
Laser Bed Size: 51 x 71
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
Ruida Controller: RDC6445
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, Prusa i3 MK3S and Mini Prusa printers.
Windows Version: Win 10 Pro

Re: Weird laser head movement problem

Post by Gene Uselman »

That would point toward the controller, or a program 'stuck' in the controller somehow? I assume that it worked normally in the first machine? Perhaps check all your wiring connection to the controller one more time?
If the Help and advice you received here was of VALUE...
Please consider making a donation to maintain the RDWORKSLAB Forum.

BT48 Alpha Shopbot and 1300x1800 130W Laser

The days that I keep my gratitude higher than
my expectations, Well, I have really good days.

Ray Wylie Hubbard
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Re: Weird laser head movement problem

Post by Elias Rautio »

Everything worked perfectly on the first machine. Maybe something is wrong in controller or program, resetting to factory did not work tho.

I have gear reduction on both axis and had 40k subdivision microstepping so it was like 0.05um per step. I thought that maybe this is too much and it is more than controller can handle (400kHz or so pulse signal) so I dropped it down to 400 subdivision microstepping. Now laser head moves doesnt stop in middle of moves and it seems to go right path, but it still accelerates very slow. Changing acceleration on vendor settings does not affect at all to acceleration speed... Really weird again
Elias Rautio
Posts: 7
Joined: Fri Aug 05, 2022 10:08 am
Location: Oulu
Country: Suomi
Laser Machine Make or Type: CO2
Laser Power: 80W
Laser Bed Size: 1500x1000mm
Home Position: TL
Control Software: RDWORKS
RDWorks Version: V8.01.47
Ruida Controller: RDC6442
Accessories: Rotary axis
Windows Version: Windows 10

Re: Weird laser head movement problem

Post by Elias Rautio »

Hi Gene, I am looking for new controller, I am currently comparing different models. I see you have rdc6445, is it good or would you recommend some other controller? One thing wonders me; RDC6445 says in description it can control fiber laser source, can this be true? It would be fun some day to try upgrade second laser head with metal cutting fiber laser. Dedicated fiber laser controllers costs thousands of dollars tho so I wonder if it can be true for rdc6445
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