3D Printed Micromanipulator/Microstage

This is a micro manipulator which can also be used as a Micro stage.

It allows users to move an object in XYZ over 15mm with a few micrometer resolution and for a very low cost.

The design was heavily inspired by the few 3D printed manipulators available over the internet such as Remi_rafael one also available on this website here. Or the one on printable from BYU CMR, here.

The downside of those solution is that they are using sliding mechanism on metal bars which while working can be a bit finicky.

The solution I put forth uses stainless steel balls to create a linear ball bearing guide similar to what professional solution uses.

The solution shown here is the most basic solution, at the end there will be a few propositions for improvements or alternatives.

An important note for those who hates screwing around: Lots of screwing pieces together ahead.

For the current versions of the STL file you will need the following:

Materials:

1. 60X 10mm M3 bolt
2. 75X M3 nut
3. 6X M3 washer
4. 1X M3 threaded rod (1M)
5. 18X 3.5mm steel balls
6. 6X thrust bearing (10mm OD, 5mm ID, 4mm Thickness)
7. 2X Rectangular magnet 30mmX10mmX5mm

3D printed parts:

1. 3X bases block
2. 6X side rails block
3. 6X bearing block
4. 3X Sliding block
5. 3X wheels
6. 1X Magnet base block
7. 1X T junction block

Tools:

1. 3D printer with Filament
2. Screw driver with corresponding bits
3. Wrench for M3
4. Cutting tool for cutting M3 threaded rod to size. (I used a steel wire pliers and a bit of sand paper)
5. glue (optional)

For bolts and nuts you can buy them in bulk at many different places, here are a few of my suggestions:

https://www.accu.co.uk/

https://www.dold-mechatronik.de/

For the thrust bearings:

https://www.amazon.fr/dp/B0C1Z5ZV8W?ref=ppx_yo2ov_dt_b_fed_asin_title

https://nl.aliexpress.com/item/1005006816356278.html?search_p4p_id=20260104083239987301994259240005698109_1

for the balls:

https://nl.aliexpress.com/item/1005008080488152.html?spm=a2g0o.productlist.main.2.59591cdeTmeTLX&algo_pvid=2b5c6932-e163-49bf-a29b-f9a4d1fb0ea6

For the magnets:

https://nl.aliexpress.com/item/1005009604233985.html?spm=a2g0o.order_list.order_list_main.37.776d1802ss6hjb

If you are used to print with FDM printer than you know that different printer have different tolerances.

The good news is that plastics are quite soft compared to metal and ball bearing have small points of contact allowing the plastic to deform should the fit bit a bit too tight. (Which it should be)

The bad news is if you have a bit of loose fit, then you will need to tweak the files. (I left the freecad file which I used to make it available. Just change the ball size I used in the sketch to a slightly smaller one.)

To start with I advise only printing enough for 1 axis, test it if everything works as it should and then print the rest.

All the pieces are quite tolerant to warping due to the placement of the bolt holes, do make sure the warping is not too extreme otherwise assembling it will be harder.

Step file and freecad file can be found on printable:

https://www.printables.com/model/1541495-single-axis-micro-stage

The first step consist of taking the bases blocks and putting all the nuts and screws in their respective holes. If you are filling up the magnetic base then don't forget to place the magnet as well.

Once they are all put into place you can then take the base plate and screw it to another pieces via the 6X M3 screw. In this case I am screwing the base on the T slot but if you are starting the you will be screwing into the magnetic base.

You should first align all the screws to the holes and then push them into it. Depending on your printer tolerance this might be easy or might require a bit of forces or even turning the screws with the screwdriver. (The holes have a 3.3mm diameter on the design)

Once the plate are flushed you should start tightening the screw with the screw driver, if the screw engaged the nut then after a few turns you should start feeling the resistance shoot up dramatically. The nut should be hand tight, no need to put too much force or you risk deforming the threads. (It's only an M3 after all)

You can then take the rail blocks and the slider block (Any will do, they are symmetric) and fill it with screws and nuts.

Then place a rail block on one of the side of the base plate and screw it tight the same way you did the base plate.

Note the small hole on the face of the sliding block, this is for an M3 nut, it will serves as the driving nut for the M3 threaded rod and move the block up and down. (This one is especially tight, requires quite a bit of force and might require heat in case your machine tolerance are smaller)

Once the rail is attached to the base plate, you can set the base plate so that the rail groove is looking up and is as flat as possible.

You will then add 3 balls to the groove separated by enough distance so that they end up in a different part of the sliding block groove. You take then the sliding block groove and place it on top of the ball flush against the base block. Make sure the face of the slider block containing the 6 nuts is not visible and on the side of the base block.

Proceed to add 3 more balls in each compartment of the rail and then tilt the sliding block slightly before pushing the last rail block against the balls.

Then align the bolts with the hole and push them in, this might require a bit more force as you are coming from a slight angle. (Remember the assembly has been made smaller on purpose to get rid of all play)

Once the bolts are in, tighten them and you should now have a sliding mechanism. Different tolerance will give more or less friction when sliding. If you have excess friction even after moving the sliding block a few time, consider changing the ball size in the freecad file by increasing their size.

Take the bearing block and add the screws to them then place them on the base plate and tighten the screws.

Once the bearing block are in place, take your threaded rod and cut it to size. (I am using 62mm long rods)

On one end put two nuts and tighten them against each other as to lock them with the thread. Optionally you can add a bit of super glue to make sure it doesn't move.

Then slide in a washer followed by a thrust bearing so that they push against the nuts. Proceed to slide the threaded rod through the thrust bearing block and then through the slider block and finally through the other bearing block.

The nuts and thrust bearing assembly should fit nicely in the holes. A single nut should still stick out of the assembly. (An unfortunate design flaw)

You can then add the thrust bearing followed by the washer and other 2 nuts on the other side as to complete the assembly of the drive.

You can then take a knob and put it on one the nuts. The side is for you to decide.

For multi axis assembly, you just need to repeat step 2 through 4 for every axis with exception of the Z axis which require the T junction block on top of the base block. (Fundamentally it is just adding the screws and nut again)

Once you have gone through the path of screwing all the pieces together, you en up with a 3 axis micro manipulator.

Unfortunately I do not have the necessary equipment to test the reliability of the manipulator nor the time for continuing working on this project as I have in the past.

But I do have a few improvement points/modifications in mind for those that want to push it further:

1. Backlash of the m3 driving nut can be nullified by simply adding a small spring on the threaded rod pushing against a bearing block. This will eliminate backlash at the cost of reducing travel capabilities but is very cheap and quite easy to do.
2. The nut sticking out being a design flaw: Originally the design only had a thrust bearing and a nut with glue but since this was a prototype that needed to be dismantled often, a washer and another nut were added on top of it. As for the reason it is a flaw: for the upper axis the T junction can push and even block the nut from turning effectively gripping the system. I have seen this problem even on professional designs hence why I consider this a flaw.
3. Redesigning the wheels: currently the wheels works but they can be wobbly or even fall off. Also depending on the mount of friction in your system you might not be able to drive them just by using a single finger.

Either way, thanks for reading all the way and hope this helped you.