My Macro System

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

Moderators: ChrisR, Chris S., Pau, rjlittlefield

mawyatt
Posts: 2469
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater

Post by mawyatt »

lonepal wrote:
ChrisR wrote:Something like two of these? :
https://www.mec.ca/en/product/5046-861/Air-Pillow
Dear Chris good find.

But I am not sure about that can hold the marble plate and all the equipments on it?

No information about max load or something.
If you can't find an air-pillow that can support the weight, try a bean bag pillow or small bean bag chair.

Another option would be the small bean bags they use for supporting camera lenses or the bags used for adding weight to a boom arm. These are smaller bags and a few would need to be positioned around the base.
Last edited by mawyatt on Mon Jul 03, 2017 6:41 am, edited 1 time in total.

elf
Posts: 1390
Joined: Sun Nov 18, 2007 12:10 pm

Post by elf »

One or more small tire innertubes will make a fine air pillow. I experimented with one, but ended up just using sorbothane pads.

Another type of vibration isolation is multiple coils of stranded cable. I think this would be pretty easy to make.

The hard part of any system is determining which vibration frequencies you want to control.

mawyatt
Posts: 2469
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater

Post by mawyatt »

ray_parkhurst wrote:Very nice system.

Seems 400 step motors are the norm now for NEMA17, and becoming commonly available for NEMA14 as well. This is helping to improve basic stepsize control. Does anyone have info on how well the 400 step motors do for microstepping vs 200 step?

When viewed live at 100%, how stable is your system? I've found a big variation between my systems and it seems to correlate well with the sharpness of the final images. In my vertical rig I found that the biggest culprit was the bottom adjustment rail of my bellows. Both Canon and Pentax showed the same issue. I ended up removing the bottom rail adjuster from my Pentax and directly bolting the rail to the stand. Turns out when you remove the rack gear from the rail, it exposes two pre-drilled holes that are ready to tap for 1/4" screw. They are even strategically-placed to allow coarse movement of the rail. I have given up dynamic up/down focusing, but I use the automated rail for that purpose. My system now shows no visible movements at 200% after a very short (~100msec) post-bump recovery period.
Ray,

I use 400 step motors in Wemacro and THK rails without problems, only Stackshot rail has 200 step motors. Logic seems to favor the 400 step motor because the 200 step motor will have to interpolate with half micro-stepping to get to 400 steps. I'm not sure the difference is a big deal from 200, but to start off I chose the 400 step motors.

Best,

Mike

boomblurt
Posts: 153
Joined: Sun Aug 18, 2013 1:37 am
Location: Australia

Post by boomblurt »

For vibration isolation I've used folded towels between my rig and the table... not sure of the ins and outs but it seems to work well.
Geoff

ray_parkhurst
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Location: Santa Clara, CA, USA
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Post by ray_parkhurst »

mawyatt wrote:I use 400 step motors in Wemacro and THK rails without problems, only Stackshot rail has 200 step motors. Logic seems to favor the 400 step motor because the 200 step motor will have to interpolate with half micro-stepping to get to 400 steps. I'm not sure the difference is a big deal from 200, but to start off I chose the 400 step motors.
I agree, logic does point in favor of 400 steps for accuracy.

I'd think it would be easy to replace the Stackshot 200 step motor with a 400 step type should be fairly easy. What size motor is used by the Stackshot?

mawyatt
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Location: Clearwater

Post by mawyatt »

Ray,

Think it's a NEMA 17.

Mike

boomblurt
Posts: 153
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Location: Australia

Post by boomblurt »

I just ordered the Wemacro and initially was going to get a 400-step motor but went for the 200-step version. The standard wemacro seems to perform well at 1um, which is enough for a 50x Mitu. Also I've read that 200-step motors might handle a vertical load a little better.
Geoff

lonepal
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Location: Turkey

Post by lonepal »

I have both 400 steppers on my wemacro and newport 436 and I get very good results with wemacro controller.
Regards.
Omer

mawyatt
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Location: Clearwater

Post by mawyatt »

Geoff,

The Wemcaro is an excellent rail system for the $. I just happen to have the 400 step version. If you are going to get into the higher magnifications be sure to consider Off Axis Loading the rail, this really helps the regard to wobble.

Think you are correct about the load handling, seems the more steps the less load capability. Load handling at micro-step positions might be less too, but I'm not a stepper motor expert so can't say for sure.

William at Wemacro has a nice vertical stand too, but I haven't had time to put it to the test. Hopefully in the next few weeks.

Best,

Mike

ray_parkhurst
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Post by ray_parkhurst »

NEMA17 0.9deg/400-step motors are easy to source and cheap, though if you want one with dual-shaft so you can do manual adjustment you'll be disappointed.

I don't think there is a general rule about 400 vs 200 step for load handling. Each type has a full range of capability.

One thing that is a bit annoying about 400 step motors is they move at half the speed! A 400 step motor on a 1mm pitch rail moves agonizingly slowly. I have a 400 step motor on my KR26 rail with 2mm pitch, and it takes a while to move the full range. I'm even considering changing it to a 200 step for this reason. I can live with 10um basic step, with 2.5um quarter steps, for most of my work below 10x. I can just piggyback a voice coil motor if I need finer steps. I recently picked up a 100mm SKR20, which has 1mm pitch, and plan to install a 400 step motor to see if I can get it to approach the resolution of the voice coil motor, but over a wider range. I can envision the SKR20/400 mounted on a KR26/200 to give quick movement plus ultra fine steps.

Edited to add: looking over the Lin stepper motor page, it does seem that the 1.8deg motors in general have higher holding torque than the 0.9deg, but both are available over a wide range so I don't think there is a limitation in our application.

Also realized that it actually takes very little holding torque to keep a vertical setup stable due to the action of the drive screw. I am using the smallest motors I can find for my vertical setups, and they work fine without movement. It takes a lot of force to move the unloaded rail at all, and even just attaching a motor without powering it up makes movement almost impossible.

I did see this on the Lin site, for those wishing even more resolution...800 steps, 0.45deg, but only in NEMA23:

https://www.linengineering.com/products ... dard_motor

Daniel_Han
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Location: Australia
Contact:

Post by Daniel_Han »

Hey, really nice setup! :)
Which bellows are you using?
Thanks.
The world of Macro is a world that most people are missing.

lonepal
Posts: 309
Joined: Sat Jan 28, 2017 12:26 pm
Location: Turkey

Post by lonepal »

Daniel_Han wrote:Hey, really nice setup! :)
Which bellows are you using?
Thanks.
Hi Daniel thanks!

I use an Asahi Pentax M42 bellows.
They have double rail, very smooth and durable.
Regards.
Omer

lonepal
Posts: 309
Joined: Sat Jan 28, 2017 12:26 pm
Location: Turkey

Post by lonepal »

Hi again;

I finally finished my vertical rail too.
Please check the photos.
I am open for any advices, thanks!

ImageVertical Rail by Omercan Calik, on Flickr

More Photos : http://flic.kr/s/aHskB1kK8N
Regards.
Omer

mawyatt
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Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater

Post by mawyatt »

Omer,

Like the brackets for the thick vertical plate and the heavy thick metal base with the rubber feet.

Very nice setup :D

One question I have is, why are the bellows extended so far from the motorized focus stage? Seems a micro-positioning stage between the focus stage and bellows base that allows movement in the same axis as the focus stage.

Could this be eliminated to get the bellows closer to the focus stage for possibly more stability, since movement is in the same axis as the focus stage movement? This is a question, not a criticism of your well crafted setup :D

So, when will we see some results from all your hard work :)

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

Deanimator
Posts: 828
Joined: Tue Oct 23, 2012 7:01 pm
Location: Rocky River, Ohio, U.S.A.

Post by Deanimator »

lonepal wrote:Hi again;

I finally finished my vertical rail too.
Please check the photos.
I am open for any advices, thanks!

ImageVertical Rail by Omercan Calik, on Flickr

More Photos : http://flic.kr/s/aHskB1kK8N
It looks pretty solid.

I'd like to make something similar, but my metal working resources are strictly limited.

Instead I've gone with a thick wooden cutting board and interchangeable wooden furniture feet that screw into a threaded insert in the cutting board. So far it seems to have worked relatively well up to 10x.

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