Build a 3D Printed Goniometric Stage (tilt Correction Stage)

I have recently undertaken to design a complete set of 3D printed tools for high precision positioning. You can find my printed micromanipulator here, my set of linear translation stages here, and my in-plane rotation stage here. This instructable will show in details the building process of my goniometric stage (out-of-plane rotation called RY stage for Rotation around the Y axis).

For all these tools, my design objectives where to achieve high precision (positioning accuracy below 10 micron) while keeping the build very economical (under 5 USD) and using only easy to procure standard mechanical elements.

To build this stage you will need the following tools:

• A 3D printer
• A pair of pliers
• Screwdrivers
• Hot melt insert tool (soldering iron or lighter if you don't have better available)

You will also need: (the links are only given as references)

• 8x 693ZZ (3mm in, 8mm out, 4mm thick) ball bearing amazon, taobao
• 2x MR95-ZZ (5mm in, 9mm out 3mm thick) ball bearing amazon, taobao
• 22x (or optionally 15x) hot melt inserts amazon, taobao
• 4x 8mm, 12x 14mm M3 screws (7x nuts) amazon, taobao
• 1x M5 73mm bolt (you will need to cut it to size) amazon, taobao
• 1x M5 nyloc nut amazon, taobao
• 1x M3 headless screw (5 to 10mm) amazon, taobao

Like all the stages of this series, this design has a 65mm square base. It is 35mm thick, can rotate over 30 degrees (+15 degrees in both senses around the horizontal) and has a center of rotation located 50mm above the center of its top surface.

Mounting holes are available on the top and bottom surfaces to attach the stage with M3 screws. They are organized in 20mm arrays. The bottom holes are can be reached after removing the "RY stage table".

I started to design these stages after seeing that inexpensive metal rods could make for very good printed mechanisms (see here) and i designed my rotational stages to allow the control over all degrees of freedom but this stage is the most mechanically complex of the series. As such it contains many adjustable/removable features and just as many sources of play. at the same time it is made of plastic and will deform if you try to tighten it too much. For this reason i would like to encourage you to first build the whole stage, then check its "smoothness" and come back to each adjustment screw to tighten it gently and eliminate all play.

To build this stage you will need to print 1x "RY stage table", 1x "RY stage base", 2x "RY stage slide", 2x "bearing holder", 1x "M5 spacer" and 1x "M5 knob".

All files can be found here: makerworld, printable, thingiverse

Among those parts only the "M5 knob" require supports. The "RY stage table" also comports some fine geometries used to connect to the driving bolt. You may want to use a specially detailed printing profile with this part. In case those details are not correctly printed it may cause an increased wear on the part.

To build this stage, start by adding holt melt inserts in the two "bearing holder" (2 inserts each) and in the "RY stage table". Make sure the inserts do not emerge from the table as it would make the later assembly challenging.

I used plain printed holes whenever possible but those threaded holes need to be assembled/disassembled multiple times and/or sustain significant forces so inserts are necessary.

You should also insert M5 nuts in the hexagonal holes of the "bearing inserts"

Insert 693ZZ bearings in the 4 recesses of the "RY stage base" and use 14mm screws to hold them in place. internal hex bolt are strongly recommended as the base is designed to support the screw head and prevent long term creep of the plastic.

Fix the two remaining 693ZZ bearings to the two "bearing holder", using also 14mm screws.

You can now attach the "bearing holder" to the "RY stage base" with 8mm screws. Start by screwing only a few turns and add the "RY stage slide" in position. Then adjust the screws until the slide is secured in position without play, but make sure the tension is not too high and the slide can freely move along its course.

Also try to keep the two screw on each side adjusted equally. If not the central bearing will be placed slightly to the side of the stage.

Fix the "RY stage table" in between the two slides and hold it with 6x 14mm M3 bolts. At this stage you should check that the table rotates smoothly without any jerk or play. Otherwise, adjust the "bearing holder" fixation screw until it gets better.

To assemble the driving screw, start by inserting an MR95-ZZ ball bearing in the front hole of the "RY stage base", then add the "M5 spacer" and the M5 bolt.

On the other side of the base, insert the second MR95-ZZ and the Nyloc nut. Use a thin tipped plier to hold the nut and screw it on until the bolt can no longer move back and forth.

The rotation of this stage is determined by the movement of the driving screw against the worn gear printed in the "RY stage table". Thus the tension between the screw and the worn gear is critical and needs to be adjusted. In this design the adjustment is realized by controlling the position of the second MR95-ZZ bearing in its slot using a headless M3 screw. To finalize the assembly add an hot melt insert in the bottom hole of the base bellow the MR95-ZZ bearing and insert a headless screw. Tighten it until the driving screw is forced against the worn gear and the rotation of the driving screw is tightly linked to the stage movements. Do not over tighten the mechanism as it would cause premature wear.

You can then add the "M5 knob" on the driving bolt and the top hot melt inserts depending on your needs.