Newbie Progress Report - Servo & Speed Reducer

[gr8legs]

A while ago the 'Heavy Duty Sewing Bug" bit me (apparently there is no vaccine or anti-venom) and I started researching commercial duty sewing machines and haunting eBay and craigslist.

Perusing these forums was / is very helpful and I now offer an interim progress report.

1: Found a Seiko CW-8B at a reasonable price. Bought a Family servo motor. Reading the posts here gave me the impression that these motors used a photocell and variable-density film segment for speed control. OK, I'm cool with that. More details later.

2: Purchased an Ikea rolling table at a yard sale for $20. Steel frame, big casters, I could sit on it and not splay the legs. Should support a sewing machine.

I thought a speed reducer would be nice but not in the budget at the moment so postponed.

Big box arrived with sewing machine head. UPS driver said I owed her a truss payment.Negotiations are ongoing. Smaller box with servo motor also arrived.

Got all the pieces into the shop and played multi-dimensional Tetris figuring out how to make these pieces work together. Formulated a plan.

Implemented the plan. Mostly worked but it became obvious that the servo motor wouldn't have enough 'oomph' at low speeds to be controllable. I was still too cheap to spring for a speed reducer - plus the physical setup was not amenable to adding one without a major re-design and re-work. I'm too lazy for that sort of shenanigans.

Designed and 3D printed two new pulleys - a big one for the sewing head (7" is as big as I can 3D print) and a 1.5" for the servo motor shaft. Cool - works fine. Gives about a 4:1 speed reduction. Removed the brake pad from the motor so the big pulley (now it's officially a 'Handwheel") can be used for fine machine jogging.

The original plan was to replace the photo detector speed control with a foot potentiometer. Great idea except the motors apparently now use a Hall Effect linear magnetic sensor device for speed control. Probably I can replace that with a pot but will need to research it a bit. Hindsight: should have gotten a 3-phase motor and VFD package from Dealer's Electric for about $170 and been done with it. 

But at least now, after Mickey Mousing a foot pedal to the speed control arm, I can sew a bit. Now on to machine tuning and timing.

 

[garypl]

Nice work putting that all together!  I like that handwheel - how durable would you expect it to be?  This whole 3D printing thing is hard for me to understand!

I am using a speed reducer that I bought from Cowboy Bob and it was very simple to install.  Simply remove the motor, attach the speed reducer where the motor was mounted, then bolt the motor to the bottom of the speed reducer frame and use another belt to connect the two assemblies.  I was able to use the original belt to connect the speed reducer to the machine head.

Gary

Edited August 6, 2018 by garypl

[brmax]

Thats a really nice job you did there. No doubt its just Cool !

I have no worries its plenty strong, in that I too am curious.

So what kind of plastic does one have as their typical choices in some projects as this.  

 

Again great job, thanks 

Floyd

[dikman]

Nice job! Good to see you've been doing your homework before jumping in. Fitting the smaller/larger pulleys is actually a great way to reduce the speed of the machine, and if you fit a reducer later it will just crawl along!! As for the pot control, it shouldn't be too hard to fabricate a suitable conventional foot control pedal?

Any chance you might post the files for those pulleys? I tend to collect useful-looking files, just-in-case .

[gr8legs]

On 8/6/2018 at 3:45 PM, dikman said:

Any chance you might post the files for those pulleys? I tend to collect useful-looking files, just-in-case .

The STL files for both pulleys are attached - happy to share. Also, if you're looking for a freeware 3D cad program I use SolveSpace  (www.solvespace.com) and am happy with it. It won't open STL files, if you'd like the SolveSpace source files let me know and I'll post them also.

 

On 8/6/2018 at 11:14 AM, brmax said:

So what kind of plastic does one have as their typical choices in some projects as this.  

This was PLA material - not really the strongest and occasionally somewhat brittle and probably the easiest stuff to 3D print with - but hey, if I break one OK can just print a replacement, right? The large pulley web is 1/4" or so thick so there's lots of 'meat' on the bones.

SewingBigPulley_4.stl

SewingMotorPulley_4.stl

Edited August 8, 2018 by gr8legs

[dikman]

Excellent! Thanks gr8legs. Perhaps if you post all the files in the 3d printer section, as anyone looking is likely to go there first?

As for PLA, I've been surprised just how tough it is.

[Wizcrafts]

2 hours ago, gr8legs said:

The STL files for both pulleys are attached - happy to share. Also, if you're looking for a freeware 3D cad program I use SolveSpace  (www.solvespace.com) and am happy with it. It won't open STL files, if you'd like the SolveSpace source files let me know and I'll post them also.

 

This was PLA material - not really the strongest and occasionally somewhat brittle and probably the easiest stuff to 3D print with - but hey, if I break one OK can just print a replacement, right? The large pulley web is 1/4" or so thick so there's lots of 'meat' on the bones.

SewingBigPulley_4.stl

SewingMotorPulley_4.stl

We now have a separate section of the forum where 3D printers and Laser Cutters are discussed and plans posted. If you get time, would you post your photo and files of the 3D printed pulleys in that forum for others to benefit from?

[DrmCa]

PLA is actually surprisingly strong. I just finished printing and putting together a monitor stand for a 23" LCD monitor and it's just as strong as the factory with fewer stiffeners. This pulley should last a long time. How did you avoid warpage?

[chris032188]

ressurecting an old thread, but do you have the orginial diameter of these? For whatever reason my cura is loading these at 4500MM and I am trying to figure how much to scale down.

[sbrownn]

On 8/8/2018 at 12:18 PM, DrmCa said:

PLA is actually surprisingly strong. I just finished printing and putting together a monitor stand for a 23" LCD monitor and it's just as strong as the factory with fewer stiffeners. This pulley should last a long time. How did you avoid warpage?

I agree.  I used to do all of my printing in ABS because I was concerned about strength but after changing over to PLA I have to say I don't see a difference in strength but PLA is way less problematic to print.

[sbrownn]

2 minutes ago, sbrownn said:

I agree.  I used to do all of my printing in ABS because I was concerned about strength but after changing over to PLA I have to say I don't see a difference in strength but PLA is way less problematic to print.

I'll probably  be switching over to PETG filament as its somewhere between ABS and PLA.

[chris032188]

3 hours ago, sbrownn said:

I agree.  I used to do all of my printing in ABS because I was concerned about strength but after changing over to PLA I have to say I don't see a difference in strength but PLA is way less problematic to print.

 

3 hours ago, sbrownn said:

I'll probably  be switching over to PETG filament as its somewhere between ABS and PLA.

 

I been printing with PETG, it really isnt that hard. People made it seem like it was goiung to be so much harder then PLA. I basically upped the temp and its pretty damn good. Any idea what size pulley the OP posted is ? Cura is making it huge when I load the STL.

[sbrownn]

1 hour ago, chris032188 said:

Cura is making it huge when I load the STL.

Are you sure it isn't the units you are using?  Maybe it was designed in millimeters and Cura is reading it in inches?

[dikman]

I opened it with Cura and it showed 190.5mm, so about 8". I tried Slic3r, same result.

[RockyAussie]

3 hours ago, dikman said:

I opened it with Cura and it showed 190.5mm, so about 8". I tried Slic3r, same result.

Same here

[Doc Reaper]

Now I’m guessing that the body of the machine is a type of cast metal. GET A SPEED REDUCER!  It will be a god send! What is the thickest you can sew? I understand you are on a budget, we all are (unless you can embezzle billions from the government) but the speed reducer will also allow better power to the needle. I have an older 1541 that came without a reducer,  it was holy crap fast! I needed more control so I placed a reducer (always use a heavy cast metal one) on it, now I can go one stitch every 3 seconds if I want and still have Piercing power