Who's running servos?

If you have made Upgrades and/or Modifications to your machine, let us know about them here.
David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Who's running servos?

Postby David J Fisher » Wed Aug 31, 2016 12:27 pm

Just got my machine about two weeks back. Initial impressions are positive. Well built, decent components, happy camper. Save for the stepper motors. I asked Redsail if I could spec machine with servos when I purchased it. I was assured that such a machine doesn't need servos. I'm getting really grainy engravings in acrylic. I've watched Russ's video about his stepper motor issues. I'm pretty sure the steps of the motor are ringing out through out the machine and into the part. If you have ever spun an unplugged stepper by hand, you know the feel of the steps. I'm gong to swap the motors out for servos and see if it goes away. I'm running a top wisdom controller and it looks like it should be a simple conversion. Curious as to who here has done it.
Redsail m900 90/100 Reci w2 TR
Dave

User avatar
Keith Sherwin
Site Admin
Posts: 1000
Joined: Fri Jun 24, 2016 1:44 pm
Location: Okanagan Valley, B.C. Canada

Re: Who's running servos?

Postby Keith Sherwin » Wed Aug 31, 2016 12:49 pm

69 Real (80)Watt Laser w/multi FL lenses. T.L.
Made 5 CNC's, Electronics, Electrical, PLC & Computer background.
:idea: Started this forum - Using RDWorks V8.01.21 on W7 Pro
Lead in creation of the RDWorksLab English Manual.
Crazy Uncle Keith!

Abraham Saenz
Posts: 42
Joined: Wed Jul 13, 2016 1:48 pm
Location: Panama
Contact:

Re: Who's running servos?

Postby Abraham Saenz » Mon Sep 05, 2016 11:36 am

Not running servos here, but did improve a lot by upgrading my stepper motor drivers to digital ones. My selection was the EM-503.

I was told the same thing, yet, the results speak for themselves. These guys really don't care that much about high quality, most of their customer just look for the machine that produces the fastest results with reasonable quality, so when they tell you that the machine does not need servos, they talk from the speed perspective, there is so much mechanical drag on this systems that it makes servos almost pointless.

On my particular machine, I would have to upgrade almost all drive components (belts, pulleys, bearings, etc...), as well as get or fabricate a smaller, lighter weight cutting head to be able to fully take advantage of servos.
Acctek AKJ6040+Clearpath Servos+90W EFR laser tube, 1.5 inch lens, polyurethane belts, Boeshield T-9 Lub :)

David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Re: Who's running servos?

Postby David J Fisher » Wed Sep 07, 2016 12:37 pm

Interesting. I have a lot of drag on my machine as well. Not sure where it's coming from. The bearing rails are decent quality. But when the machine is off positioning the head manually is no where near as Easy as I thought it would be. It's not hard but stiff to move. I'm going to servos. Leadshine Blm series. I figure it can't hurt. I've got one of the motors/driver encoder but am waiting for the second one in the mail. I'll write up what i figure out. I wonder what the best approach decreasing the drag would be.
Redsail m900 90/100 Reci w2 TR
Dave

User avatar
Gene Uselman
Posts: 794
Joined: Thu Jul 07, 2016 1:18 pm
Location: Suburban Minneapolis, Minnesota, US

Re: Who's running servos?

Postby Gene Uselman » Wed Sep 07, 2016 12:58 pm

Not sure which axis you are talking about but if it is the Y- make sure the rails are parallel. If you disconnect the belts you should get a good indication of your actual drag. Gene
Gene- 130W 1300x900 China Laser with 2" FL lens
V8.01.19 RDWorks on Win 7 pro
500mm Z, blade table machine home is upper right.

100W Reci tube in a Bodor BCL0605MU V8.01.19
600x500x 200Z, SS table, 2" FL- mach home upper right
Vectric Aspire software- FlexiSignPro- vector/bitmap

Abraham Saenz
Posts: 42
Joined: Wed Jul 13, 2016 1:48 pm
Location: Panama
Contact:

Re: Who's running servos?

Postby Abraham Saenz » Thu Sep 08, 2016 1:08 pm

David J Fisher wrote:Interesting. I have a lot of drag on my machine as well. Not sure where it's coming from. The bearing rails are decent quality. But when the machine is off positioning the head manually is no where near as Easy as I thought it would be. It's not hard but stiff to move. I'm going to servos. Leadshine Blm series. I figure it can't hurt. I've got one of the motors/driver encoder but am waiting for the second one in the mail. I'll write up what i figure out. I wonder what the best approach decreasing the drag would be.


Please post your results after the servos, I confess that I just did not have the courage to get them. Have you researched on the Clear Path line of servos?

https://www.teknic.com/model-info/CPM-SDSK-2321S-ELN/

The have integrated controller and they have moders that would work with step and direction inputs supposedly.

They seem to offer tremendous value for the money and are made in the US on to of that
Acctek AKJ6040+Clearpath Servos+90W EFR laser tube, 1.5 inch lens, polyurethane belts, Boeshield T-9 Lub :)

David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Re: Who's running servos?

Postby David J Fisher » Thu Sep 08, 2016 3:09 pm

I am familiar with the teknic line. I love some usa made stuff too. I'm big into old wood working machines. However for this project I felt like the leadshine servo motors fit the bill better. Slightly smaller footprint, and cheaper.

I will deff report back when they arrive
Redsail m900 90/100 Reci w2 TR
Dave

David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Re: Who's running servos?

Postby David J Fisher » Fri Sep 09, 2016 12:31 pm

Well the second servo cleared customs. Should only be another few days till we swap them out. Shane good to see another North Carolinian, Asheville here.
Redsail m900 90/100 Reci w2 TR
Dave

David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Re: Who's running servos?

Postby David J Fisher » Wed Sep 14, 2016 4:05 pm

On my machine the sync pulley on the stepper motor is a press fit. The other pulleys are not. They are a really tight press fit. I've just about got it worked off the shaft, but have most likely trashed the stepper motor in the process. No big deal. My machine runs a 24 tooth 3m pitch ~8mm bore pulley. If anyone knows of a domestic source for such things please let me know. I've got one coming via amazon tomorrow, but they only had one in stock. I do not want to use any force installing the sync pulleys to the servo for obvious reasons. I heated the pulley to remove it, but it didn't do much to help. Hopefully I can find the correct pulleys with set screws. Plan b is to remove the existing pulleys have them bored out slightly and drilled/tapped for a set screw.

So just a heads up for anyone considering this upgrade. Check your drive pulleys.

Servos are so freaking cool. We wired it up on the bench and got the tuner software communicating with the motor. So fast. If this works out well, I will be changing out all my steppers for servos on my cnc machine. Machine is down at the moment, hope to be back up with servos soon.
Redsail m900 90/100 Reci w2 TR
Dave

David J Fisher
Posts: 21
Joined: Wed Jul 13, 2016 3:16 pm
Location: North Carolina

Re: Who's running servos?

Postby David J Fisher » Thu Sep 22, 2016 1:20 pm

Update: The pulleys turned out to be a headache. I tried for two days to get in touch with my machinist but had no luck. The pulley I ordered off amazon arrived with the wrong bore. Seemingly only China could source this pulley. After much head banging and hand wringing, I devised a plan. I ended up using my siegx2 cnc converted mini mill to cut a tight fitting pocket in a block of wood. I then fully inserted the geared pulley into the pocket. I then used a quarter inch router bit to bore out the pulley. I don't have my log in front of me for exact numbers, but it took about 20 step downs to complete the bore. It was taking very light bites and using a finishing pass. I was amazed by how well this worked. Or maybe that it took me two days to come up with the plan. I just kept thinking it had to be done on a lathe. I then drilled and tapped the pulleys for a set screw.

Lesson #2: Just because it look like a nema 23 doesn't mean that it is. Once the pulleys were on the motors it was time to mount the motors. I don't know what the steppers on my machine were, but they are certainly not nema 23. I had some other nema 23's that I measured to verify this. They were off by about 8 mill or so if I recall. We were able to turn the mounting holes into slots and attach with nuts and lock washers. Not ideal, but its working fine.

With the motors in place, it was time to tune. We had already bench tested the drives and servos, but you really don't know anything until the system is under load. Tuning was accomplished via a serial connection to a laptop running the provided software. No real problems there. Only minor issue is that when you load the software you have to select your drive. In my case it was acs606, it would not communicate with the drive until I changed that over to acs606 version 2. Everything worked fine then, however it incorrectly displayed the connected drive as an acs806. This didn't seem to matter. The software is solid, and there is plenty of online info / youtube info available.

Now it was time to route the cables. This is kinda tricky. On my machine the stepper wires in a loom with the pointer light and some other stuff so I opted just to leave them. Servos however have two cables one for power and one for com. The power one is easy enough but the com one is de15 (think vga) 15 pin connector.

The drag chain on my machine is cheap. It doesn't latch open. You have to pull the cables through with a pull cable. This was not very fun but doable. The real downside here is that the com connector for the servo has to be removed. The connector comes apart and inside it is sealed with some substance that resembles hot melt but just turns to gummy nasty stuff when heated. Luckily my partner in this laser venture is an electronics guy and he had a clean spare. Luckily for me, he also took care of most of the cable running, including re soldering the 13 conductor wire to the new de15 connector ;)

And that's pretty much it. We have it working and all seems well. We had to improvise more than I like, but hey the way she goes. The servo cable included was just barely long enough to make it through the drag chain. It comes with an extension, which we used, but that joint can't exist inside of the drag chain. We are currently running it off the same power supplies that the steppers were running on. I think 36v at 6amps. That all seems fine, great thing being that the max load is pretty much fixed on this type of machine.

Initial impressions are positive. I should have taken much better "before shots." I wanted to set an accurate ruler and a gopro up inside the machine to try and figure out the real speed. I don't trust the controller. Maybe I'm crazy. But my machine supposedly will run at 1000 mm/s on steppers. I think the steppers were maxing out at a slower speed. I could be completely wrong about that. Anyway the servos are fast. Really fast. Holding torque is good. When I was dialing in the machine with the servos, I mainly drew 100 x 100 mm to figure out the resolution. That was pretty routine, however when I did my first raster I was really surprised.

I ran it fast like 750 or 1000. The image came out in double about a quarter inch apart. I never experienced any of this with steppers. I then drew out 3 50 x 50 squares at 2dpi per the manuals instructions. From there I was able to run test and get most of the backlash out. I found that the backlash got much worse the faster the machine ran. I seemed to get the best results at around 300 mm/s. At high speeds the lines trailed off with out great definition. I'm assuming that we are maxing out the minimum pulse interval on the tube. I just don't know why the double vission wasn't an issue with the steppers.

So I think the upgrade is worth it for some people. The engraving quality in plexi seems much better. I will run more quantitative test in the upcoming weeks. The speed is there, but I'm not sure how use full it really is. I plan to go back and upgrade the servo cable and drag chain at some point with igus latching chain. This works for now. I was really impressed by the quality and documentation of the leadshine blm servo motor line. Everything worked as it should. We had a question about the pinout and wire color when we were soldering the new connector on. The leadshine website had all of this info and a lot more. Even the wire colors. The machine runs a lot quieter now which I really like. I apologize for the lack of specifics, I'm working of memory, and wanted to sum up my experience. If you have any questions let me know.

-Dave
Redsail m900 90/100 Reci w2 TR
Dave


Return to “Upgrades and Modifications”

Who is online

Users browsing this forum: No registered users and 1 guest