THK KR15 cheap on eBay

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ray_parkhurst
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THK KR15 cheap on eBay

Post by ray_parkhurst »

Great deal on these KR15's including steppers. I purchased several of these from this seller at $80 each and thought it was a steal!

https://www.ebay.com/itm/THK-KR15-Linea ... 5051!US!-1

ray_parkhurst
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Post by ray_parkhurst »

I've had several PMs regarding this rail so thought I'd add more info...

The rail is very small, with only 30mm of travel. I consider it mostly suitable for moving subject. I use them in my XY stage for this purpose.

The motor supplied cannot be driven directly by a Stackshot/WeMacro/mjkzz motor controller without modification. The back end of the motor has a housing which contains a RS485 serial communications IC and a motor control chip. The motor manufacturer makes software available for controlling the motor. The controller can be removed and the motor wired for use with our more familiar controllers.

Hope this helps...Ray

JohnyM
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Post by JohnyM »

This is THK1501A standard type, here's PDF for it:
https://tech.thk.com/en/products/pdfs/en_a02_098.pdf

I have one of those, and ordered 2 more to make XYZ stage for stiching, thanks Ray!

I have to admit, i have no idea how to control all those electronics. Rails also have some kind of extreme positions sensors. I've planned to adapt them to wemacro controller (AFAIK they are working on XYZ controller / soft for multiple controllers). Ray, can you provide some insights on manuracturer software? I have to admit my knowledge in this field is extremely limited.

ray_parkhurst
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Post by ray_parkhurst »

The software is a pretty basic command-line affair from the motor mfr. Here is the web page with downloads for manuals, software, etc so you can see what you're up against:

http://usautomation.com/Accuriss28.aspx

You need to provide a RS485 serial interface, which is easiest to do with a USB-RS485 converter. I guess RS485 cards are also available. This is a similar requirement for the Trinamic system as most of the Trinamic interfaces I've seen are RS485.

Note that I indeed got this system working for a single axis, but not being much of a programmer I ended up buying the mjkzz S&S system and am now using it instead.

Edited to add: indeed the rails have position sensors that can be interfaced with the more familiar controllers. This is not required for operation, especially if you manually set the start.stop points and avoid the extremes.

Macro_Cosmos
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Post by Macro_Cosmos »

Silly question, would it be possible to just replace the cord so it can be connected to my stackshot or wemacro controllers? I'm too busy to do research, I honestly shouldn't be lurking here at all. Back to my research project.

Thanks in advance.

ray_parkhurst
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Post by ray_parkhurst »

Macro_Cosmos wrote:Silly question, would it be possible to just replace the cord so it can be connected to my stackshot or wemacro controllers? I'm too busy to do research, I honestly shouldn't be lurking here at all. Back to my research project.

Thanks in advance.
Yes, the controller can be removed and the 4 motor wires accessed directly.

edited to add:

Here is the color mapping from the motor to the mjkzz cable:

Image

JohnyM
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Post by JohnyM »

Thanks Ray.
Finally, that last picture is something that i can understand :)

Macro_Cosmos
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Post by Macro_Cosmos »

ray_parkhurst wrote:
Macro_Cosmos wrote:Silly question, would it be possible to just replace the cord so it can be connected to my stackshot or wemacro controllers? I'm too busy to do research, I honestly shouldn't be lurking here at all. Back to my research project.

Thanks in advance.
Yes, the controller can be removed and the 4 motor wires accessed directly.

edited to add:
-Image Above-
Many thanks!

Macro_Cosmos
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Post by Macro_Cosmos »


houstontx
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Post by houstontx »

In your professional opinions would this be a good rail to build a simple stack system with? Whats the max steps it can do? Could I attach a camera to it & do a 300 image stack at 0.1 micron per step? Thanks

edit: i bought the last one :oops:

ray_parkhurst
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Post by ray_parkhurst »

houstontx wrote:In your professional opinions would this be a good rail to build a simple stack system with? Whats the max steps it can do? Could I attach a camera to it & do a 300 image stack at 0.1 micron per step? Thanks

edit: i bought the last one :oops:
As I stated above, this rail is very small. IMO it is not suitable for direct-mounting of a camera or lens mount to its carriage due to the static and dynamic moments such a weight would cause. However, if an idler rail is added, and the idler and KR15 carriages connected with a long arca rail or other solid connection, this rail could certainly do the job.

The rail has 1mm pitch. The motor supplied is 200 steps per revolution. I only count on 1/4 step microstepping to be useful, though 1/8 might be OK if you adjust the drive and static currents appropriately. So for sure you can count on 1/200 or 5um per full step, and almost as certainly on 1/200/4 or 1.25um per quarter step. But even with 1/8 step you are only getting to 0.625um per, so if your goal is to do 0.1um, this system won't do it.

Out of curiosity, what would you use such a small step for?

houstontx
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Post by houstontx »

I wouldn't, I probably won't do anything more than 30 or 60 maybe, but its good to know the limits as I'm not familiar with all the calcs. I have a massive granite plate with mounting holes, I was thinking using that as a base for a stacking system, would that allow this rail to support a camera better? The rail was $60 delivered on my end, and it looked like there was a lot of support for the THK system and integration with the various controllers from the forum. Hoping its a good rail to try an adapt a simple horizontal setup. I plan on using a leitz bullet positioner from a forensic comparison scope to move and illuminate the subject (also bolted to the granite plate).

ray_parkhurst
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Post by ray_parkhurst »

houstontx wrote:
edit: i bought the last one :oops:
Looks like the seller put two more up at same price. The new ones have a different carriage adapter, this time with some sort of lens holder, maybe for 1" lens. Otherwise looks the same, and the end users will probably end up removing that adapter anyway unless they will be using the limit switches.

viktor j nilsson
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Post by viktor j nilsson »

And I got one of the other ones :oops:

I've been tempted for a while to convert my manual (Newport stage) horizonal setup into an automated one. When I saw your recommendation (and especially the picture with it connected to the Mjkzz controller) I couldn't resist. With eBay's shipping and import charges, it's not often that anything feels like a bargain these days.

30mm travel is more than enough for me.

Sounds like a good idea to add an idler rail. But I might try without one first to see how it works. Putting a 7D, bellows and microscope objective on it isn't going to break it, right? Just make the movement uneven?

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Post by ray_parkhurst »

viktor j nilsson wrote:And I got one of the other ones :oops:

I've been tempted for a while to convert my manual (Newport stage) horizonal setup into an automated one. When I saw your recommendation (and especially the picture with it connected to the Mjkzz controller) I couldn't resist. With eBay's shipping and import charges, it's not often that anything feels like a bargain these days.

30mm travel is more than enough for me.

Sounds like a good idea to add an idler rail. But I might try without one first to see how it works. Putting a 7D, bellows and microscope objective on it isn't going to break it, right? Just make the movement uneven?
I doubt it will break! When you receive it you'll see why I say these are extremely small. Certainly using it on a horizontal setup will be less stressful than on a vertical one, so it's probably worth a try.

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