Hoddem's DIY Linear Actuator

What kind of motor is that? Washing machine or dryer? Something similar?

I'm just playing, it's a 4.25 hp treadmill motor. I just replaced it on my treadmill and before I take it to the scrap yard I figured I would throw it out there.

I updated the design to include the new connections. The power inputs are standard IEC320 receptacles and the Data port is a 8P8C breakout board that I will add terminal blocks to.

amazon.com/uxcell-Panel-Adapter-Connector-Socket/dp/B01ISO2T1C
amazon.com/Connector-Breakout-Ethernet-DMX-512-Unassambled/dp/B0120Q1WSU






I also updated some of the parts to capture the bearings rather then rely on the press fit to hold them. I noticed in my limited amount of testing that the 25mm main bearing was starting to slowly work itself out.





I am hoping to get the 3d printer going on the new parts soon, but I had a massive failure where my extruder just kept extruding into itself creating a giant ball of pla covering everything it possible could. I have some replacement parts on order and should be back up and running this weekend.

Updated the post, I had included amazon links but they never seem to work for me.

Hi,

First Material arrived, everything till now is made with 7075 aluminum. Seems to be fit together


Still waiting for the motors,

@Hoddem , the aluminum parts for the joint have to be modify for proper Assembly.

-kermit

Wow, Looks really good.

Are you saying that you can't assemble the u-joint in the current configuration? it looks like you built them as a solid piece, when I 3d printed mine like that I couldn't assemble them because there was not enough space to fit the actual u-joint in. The design now has caps with u-bolt for retainers to make assembly possible.

Also, Are you machining those in house on your home built multi-axis mill? If so you really need to do a time lapse video of it running because that is a very complex part for a home shop to make.

Yes right I made solid pieces. I modified the 3D's to make it possible to assemble the u-joint

I didn't make this complex piece on my home machine, a company made this for me. But some other parts are homemade.

Hi,

what do you use as sensor ? do you have some advices ?

thanks

Hi @Hoddem ,

i've the same issue here, neede to flip the ball nut , :-(

can you send me the step-file (or put it on your dropbox) for the adapter ? so i can flip then easely the rod.

THANKS
Kermit

It should be in the dropbox folder, look in the export folder. I have all of the custom parts exported as step 214 files in order to bring them into fusion 360.

https://www.dropbox.com/sh/xktbe5wp8bm9286/AAAYpmETkyo2VQaC_10z1lgga?dl=0

its called ball nut removal tool, let me know if you cant find it.

Got it, thanks !!!

Hi @Hoddem

One more question,

Did you print this part with 1:1 ratio or a little bit smaller for better fitting ?

-kermit

I printed at 1:1, it was still pretty loose for me even at 1:1. If you print any smaller you probably won't be able to get the end of the ballscrew to fit into the tool.

FYI to make this I grabbed a model off grabcad and shortened it. I then added a hole in the end. The part may not be an exact match to the ballscrew, but it worked well enough for me.

Here is the new connector plate with the 2 iec320 receptacles and the data port. Not my best print, but it will work for testing just fine.





I am planning on adding screw terminals to the Ethernet breakout pcb. I would like to go with 5mm terminals because I need to share the ground on 4 wires, That will require an adapter board though.

Well, I printed out some parts with the new capture design and I really wasn't very happy with the results. I decided to go another route and added set screws to the design. The set screws will hit in the groove on the linear bearing and should be plenty to prevent the bearing from working its way out.




I will have an printed parts with the new design soon

What's about your first idea to have two screw from the top to fix the bearing ?
This didn't work ?

-kermit

No it didn't work, I suppose its a limitation with 3d printing and would work just fine on machined parts or with modification to the design. On the 3d printed parts the screws were too close to the bearings and ended up compressing the entire bearing into an oval shape. I could have moved screws further away from the bearings and added washer, but I am running out of space and that design would restrict the movement slightly.

I have 1/8" of space on the bottom of the ball nut mount, its a tight fit to get the retaining screw and washer into that space.



on the large bearing any retaining screws on the bottom side will shorten the stroke by the height of the washer and screw head.



in the end I decided to go with the set screw method, it should work and will be a little cleaner.

The 3d model has been updated on grabcad with a few other tweaks, nothing major just cleaning some things up.
https://grabcad.com/library/hoddems-diy-linear-actuator-r2-1

I am working on updating all of the 3d print files now.

I didn't see this, are you asking about the encoder or the limit switched?

The encoder is from sparkfun COM-10932
www.sparkfun.com/products/10932

the limit switches are from Amazon
www.amazon.com/PODOY-Micro-Limit-Switch-Hinge/dp/B0171G7HCY/ref=sr_1_1_sspa?ie=UTF8&qid=1505931496&sr=8-1-spons&keywords=KW4-3Z-3&psc=1

I chose an encoder over a potentiometer because I will be using a kangaroo driver and I have read on the forums that the kangaroo just works better with an encoder (also encoders have unlimited rotation). However, that being said I may end up going with a kangaroo on my racing rig which has potentiometers so hopefully that's not entirely true.