I'm going to experiment with a more cost effective way to make linear stepper motors, requiring almost no purchasing of raw material but rather the modification of Hiwin style linear rails.by klcjr89 - Stepper Motors, Servo Motors, DC Motors
QuoteMKSA One important thing, it has to be soft iron and tool steel is not suitable and very hard to machine ! O1 is easy to work with since it comes unhardened (annealed) with high speed steel tooling. It only becomes much hard after you oil harden it.by klcjr89 - Stepper Motors, Servo Motors, DC Motors
Doing some more digging, I found out that each step is 250 microns, aka 4 steps per mm in full step mode. Is this too coarse for use in 3D printing on a delta printer, even if we use high microstepping such as 256? This may kill the idea?by klcjr89 - Stepper Motors, Servo Motors, DC Motors
Some more research has yielded that the platen teeth can be made by photochemical etching, which is good news I think.by klcjr89 - Stepper Motors, Servo Motors, DC Motors
QuoteVDX ... look at the images in this 11 years old thread - Especially on the images of the Brother type-wheel printer with the same "toothed steel barn" for positioning the print head. Could give you some more ideas Yes, I saw that thread Making the forcer will be a challenge but a 3D printed one for a prototype could work.by klcjr89 - Stepper Motors, Servo Motors, DC Motors
I made a thread specifically on the discussion of linear motors here:by klcjr89 - Delta Machines
I wanted to post a thread about linear stepper motors in the proper section of this forum to see how we could make these more affordable. They are very expensive; for example, a basic single axis linear stepper from H2W is $855 for a forcer, and $2,225 for a 48 in. long platen. The platen is a piece of precision ground steel bar stock, and can be found at McMaster-Carr in lengths of 1.5 ft., 3 fby klcjr89 - Stepper Motors, Servo Motors, DC Motors
Quoteo_lampe In which way are these small bearings better than V-wheels and belt? You'd also need more bearings than shown, as you are moving vertical with no gravity holding the forcer down. The precision ball bearings and the ground steel platen will be more precise than V slot which isn't ground. Extra bearings aren't needed, the permanent magnet force keeps the bearings in contact with theby klcjr89 - Delta Machines
QuoteMKSA BTW, I proposed this linear motor to tease you ! Have you seen and used them ? There is no way you could make them at home. They also run on an air cushion. In fact, it could be used but as an X Y moving table, you put the bed on it and just need a hotend moving just in Z. A good start, this one: Actually, the air cushion ones are a different model, the ball bearings ones would workby klcjr89 - Delta Machines
Quoteo_lampe How deep are the teeth? Would it be possible to etch them? About 1mm deep, so not really. QuoteDjDemonD I was thinking have the coils in the track and permanent magnets in the carriage. It's far cheaper and easier to have the coils move with the forcer then to build several coils into the length of the platen.by klcjr89 - Delta Machines
I think this would be a great printer if the prices for clear acrylic tubing in large sizes were cheaper. This company has OD sizes up to 27" and lengths up to 6 feet, but the prices are very expensive: The tolerances should be very good, and the cast tubes are much better than their extruded counterparts.by klcjr89 - Delta Machines
QuoteMKSA Quoteklcjr89 QuoteDjDemonD Maybe there's a way to encode the position information onto the power lines like homeplug type systems. On the other hand maybe some wires to the motors isn't that much of a problem. Another way would be to have a PCB with four copper tracks on it, and make an adapter that plugs into the stepper's port that has spring loaded contact pogo pins. There would beby klcjr89 - Delta Machines
QuoteDjDemonD Maybe there's a way to encode the position information onto the power lines like homeplug type systems. On the other hand maybe some wires to the motors isn't that much of a problem. Another way would be to have a PCB with four copper tracks on it, and make an adapter that plugs into the stepper's port that has spring loaded contact pogo pins. There would be one PCB per stepper motby klcjr89 - Delta Machines
@DJDemonD, I like the idea of using a linear shaft and the screw as positive and negative power for the stepper drivers fixed to the motor. I'm not sure how well WiFi or Bluetooth stepper drivers would work, they would probably need some kind of data buffer and be able to talk to the other two movement steppers. There would also need to be a way to insulate the positive and negative from shortinby klcjr89 - Delta Machines
QuoteMatthewHall Quoteklcjr89 Quote691175002 I edited my post with a few more details. The side-loads on a 3d printer might be small, but you are still looking at maybe 200-400g of acceleration depending on the speed and extruder being used. If you put that load on the very end of a 500mm rod that is only being held by a tiny section on one end it will still bend quite a bit. For example hereby klcjr89 - CoreXY Machines
QuoteDjDemonD I like the idea of the motors moving as its novel and whilst at first it might seem unnecessary, some benefits may emerge so its worth trying. My main concern is that your leadscrews will never be straight enough to prevent horrible wobble as you move up and down the axes. So you'll need to add a linear rail or rods or something in addition to the screws. Which begs the question couby klcjr89 - Delta Machines
QuoteMKSA Quoteklcjr89 Having the XY on a mic-6 plate is much better than using V slot which isn’t great when you do the measurements on a surface plate. V slots where ? What measurement ? How rigid is your mic -6 plate with a big hole in the center ? Will it even still be flat when you have mounted everything ? How about completing your built to give a clear picture. I am not sure how to cby klcjr89 - CoreXY Machines
QuoteTrakyan I don't see the fuss about trying to keep the motor stationary, I'm guessing a screw that big has more inertia when spun up than the motor does when it has to move itself. I agree it means less wiring, but that may not be the goal here. This is similar to the LISA Simpson Nicholas Seward built a while back. You can let the nut/carriage assembly rotate if you don't use parallel linksby klcjr89 - Delta Machines
QuoteMKSA Quoteklcjr89 QuoteMKSA The way you use the ball screws, they are part of the structure, the frame. Can be seen in the rendering and you wrote it initially. If you "attach" them to a frame as advised, then we are back to a more classic approach, still with plenty of issues some described above. The printer needs an enclosure regardless, so it will have top and side plates. I think the pby klcjr89 - CoreXY Machines
QuoteMKSA The way you use the ball screws, they are part of the structure, the frame. Can be seen in the rendering and you wrote it initially. If you "attach" them to a frame as advised, then we are back to a more classic approach, still with plenty of issues some described above. The printer needs an enclosure regardless, so it will have top and side plates. I think the print should be stationaby klcjr89 - CoreXY Machines
QuoteMKSA Of course they are unsuitable to be used as structural elements ( "frame") like in this proposal which condemns it. I wouldn't think of them as all that structural when the top and side plates go on to enclose the machine, other than to support the weight of the XY platform. Or were you referring to using the TR8 leadscrews as the frame and I misquoted you?by klcjr89 - CoreXY Machines
Quotefrankvdh Why not have the steppers rotate the screws? That way you aren't moving the mass of the motors, and the motor wiring doesn't need to move either. Motors attached to the top plate, and some 608ZZ or similar bearings in the bottom. That’s been done before. I’m looking at fresh new designs.by klcjr89 - Delta Machines
Quoteo_lampe QuoteIf the ballnut's OD is 40mm, I could solve this with just using a 42mm ID bushing, correct? Not really, how would you deal with the belt tension? Magic?by klcjr89 - CoreXY Machines
Hello, I came up with an interesting design that I'm not even sure if it would work, but I wanted to post it here to get positive feedback. Basically, the design uses 1/2" thick Mic-6 plates for the bottom, top, and sides, and uses three stationary ballscrews that are press fitted into the top and bottom plates. The front plate will be lexan most likely. The bed will be a seperate circular Mic-by klcjr89 - Delta Machines
Quotethe_digital_dentist You are planning on turning the nuts with the motors on the moving platform. Belts will loop around the motor pulleys and the nuts. Even if you use a "loose" bushing to hold the nuts to allow for unstraight screws, the belt tension is going to keep the nut pulled to one side (torward the motor). If the screw deviates from straight, it will still pull the moving platforby klcjr89 - CoreXY Machines
QuoteVigilant Quoteklcjr89 QuoteVigilant I do think the idea is good, but it doesn't address abnd resolve the number 1 problem with Z axis which is z banding. It should if the bushings the ballnuts rotate within have a clearance inner diameter. Example: if the OD of the ballnut was 40mm, choose a 41mm ID or comparable bushing. I'll believe it when I see the print result and how the layers alignby klcjr89 - CoreXY Machines
QuoteVigilant I do think the idea is good, but it doesn't address abnd resolve the number 1 problem with Z axis which is z banding. It should if the bushings the ballnuts rotate within have a clearance inner diameter. Example: if the OD of the ballnut was 40mm, choose a 41mm ID or comparable bushing.by klcjr89 - CoreXY Machines
Quotethe_digital_dentist Quoteklcjr89 In the reliable case of using three synchronized ballscrews with one stepper motor, would you recommend the fourth corner being a 25mm ground linear shaft? I would not recommend that configuration at all. Screws provide motive force. Guide rails provide guidance. One round guide rail allows the bed to go up and down along the axis of the rail, and allowsby klcjr89 - CoreXY Machines
Quote691175002 Virtually any ballscrew should be fine here. I remember the Chinese rolled screws being roughly a third of the price of Misumi's C10 screws, and have found them to be acceptable, so you could give that some consideration. Appropriate screw diameter depends on how they are being supported. The weak point is likely to be the connection between the base and the screw, so unless youby klcjr89 - CoreXY Machines
Quote691175002 As I mentioned before, using ballscrews as linear guides is discouraged, but the datasheets make it seem pretty plausible. Its entirely possible that screws might be smoother than the Chinese LMU parts. Right now I'm leaning on using a single motor with four ballscrews. Two questions: are 20mm ballscrews enough in diameter, why not 25mm? Lastly, Misumi has C10 ballscrews for redby klcjr89 - CoreXY Machines