Build a 3D Printed Linear Stage

Linear stages are mechanical platforms capable of precise translations in one direction. They are often used in science, like in optics to place components on a bench, in microfabrication to interact with microscopic devices or to place a sample under a microscope. But generally speaking they are very handy in a workshop, whether you want to make a complex soldering jig, do some macro photography or mount a camera.

I recently dedicated quite a few hours of my life designing a 3D printed micromanipulator (see here if you are curious) and concluded that it is possible to make very good 3D printed sliding mechanisms using inexpensive 2mm metal rods as slides. Based on this design principle i made 3 types of linear stages and this instructable is meant to illustrate the fabrication process.

Those 3 designs are: 1) a single axis translation system "X stage", 2) a two axis translation system "XY stage" and 3) a single axis translation system with the translation perpendicular to the stage: "Z stage". My design requirements where to make the systems as compact as possible, very stiff, without backlash and using only cheap, standard elements. The results cost bellow 5 USD, can be built in 10 to 20 minutes and can give you a positioning accuracy close to 10 microns.

If you like those, i have also designed two rotation axis shown in the introduction video: Link to the In-plane rotation axis RZ stage, and to the Out-of plane rotation (goniometer) RY stage.

To build any of those stages you will need the following tools:

• A 3D printer with PLA filament
• A vice
• A metal saw
• A file
• An electric drill
• (Optional) You may want to make yourself a tool by warping one extremity of a 60 to 90mm rod in tape and tissue until it makes for a comfortable handle. It will be very useful to push rods out of their holes.

To make the X stage you will need:

• 1x 55mm M3 bolt, nut and washer
• 1x spring (40/50 min/max length, 7.5 max outer diameter, 3.5 min inner diameter, 0.6 to 0.8 recommended wire diameter)
• 4X 64.5mm stainless steel rod of diameter 2mm
• 11x hot melt inserts

To make the XY stage you will need:

• 2x 55mm M3 bolt, nut and washer
• 2x spring (40/50 min/max length, 7.5 max outer diameter, 3.5 min inner diameter, 0.6 to 0.8 recommended wire diameter)
• 8X 64.5mm stainless steel rod of diameter 2mm
• 11x hot melt inserts

To make the Z stage you will need:

• 1x 55mm M3 bolt, nut and washer
• 1x spring (40/50 min/max length, 7.5 max outer diameter, 3.5 min inner diameter, 0.6 to 0.8 recommended wire diameter)
• 2x spring 20mm long (same diameter as previous one, 1 40mm spring cut in two will work fine)
• 2x 25mm (head included) M3 screws with flat or conical heads. The head diameter should be large enough to block the 20mm springs.
• 4X 25.5mm, 2x 44.5mm and 2x 61.5mm stainless steel rod of diameter 2mm
• 13x hot melt inserts

All stages are designed to be stackable and have the basic dimensions of a 65mm square. The X stage is 18mm thick and has a total course (maximum displacement) of 20mm in one direction. The XY axis is 30mm thick and also has a total course of 20mm in two directions. The Z stage has an adjustable thickness between 26 and 36mm. For the X and XY stages, the stages moves by 0.7mm per turn of the knob. For the Z stage the thickness varies by 0.24mm per turn.

All stages can be assembled and/or fixed to a substrate using 6mm M3 screws. The mounting holes are arranged in an array with a 20mm base spacing (see illustration). I plan to upload different versions compatible with standard optical tables but you can contact me if you need a specific spacing. For the X and XY stages, fixation can be done by driving the stages to their endpoints if you want to use the outer fixation holes, but in general it requires to disassemble the stage.

I tried to design this project with standard, easy to procure materials but that doesn't guarantee you will have them on stock. Here are some links to help you gather what you need. For each one, I've tried to include one link from Taobao (Chinese platform) and one from Amazon. I nevertheless would like to encourage you to find local providers and limit oversee delivery whenever possible...

• 55mm M3 bolt (up to 65 mm also works) I use mostly internal hex bolts but any kind of head type is ok if you are ready to file the head perimeter a little.

amazon, taobao

• M3 nuts and washers

amazon, taobao, amazon, taobao (only follow these links if really necessary, you most likely don't need 100...)

• 40mm springs (40/50 min/max length, 7.5 max outer diameter, 3.5 min inner diameter, 0.6 to 0.8 recommended wire diameter)

amazon or amazon, taobao

• 2 mm diameter metallic rod (stainless steel advised, at least 15mm if you want to limit the waste when cutting to size)

amazon, taobao

• M3 4.2mm diameter 4mm long melt inserts (other dimensions are possible if preferred, see 3D files description)

amazon, taobao

The 3D files for all three stages are freely available on the following websites. Take the time to read the description as various versions are available depending on the tolerances of your 3D printer and the type of hot melt insert you want to use.

X stage:

Makerworld, printable, thingiverse

XY stage:

Makerworld, printable, thingiverse

Z stage:

Makerworld, printable, thingiverse

The first step to build these stages is to cut the rods to the right dimensions (X stage 4x 64.5mm, XY stage 8x 64.5mm, and Z stage 4x 25.5, 2x 44.5 and 2x 61.5mm). You may off course do that by hand if you wish but i designed some cutting guides to help you with the task. Just fix the guide in a vice, insert the rod to the end and cut at the extremity. To facilitate the insertion, i recommend making a chamfer at one of the rod's extremities by holding it in a drill and spinning the tip against a file.

For the X stage you will need the 3D printed parts: 1x "X stage base", 1x "X stage table" and 1x "knob".

First place the M3 nut at the extremity of the bolt and place it in the hexagonal hole of the "X stage table". Fit should be tight. You can heat the nut a few seconds with a lighter to help the insertion. If the nut does not hold in place by itself you should glue it.

After that place the "X stage base" and "X stage table" together and insert the rods in the holes. At this point the holes should be slightly undersized and the parts should have difficulties sliding. You can use a rod and a drill to adjust the hole size until the two parts can slide smoothly together. Please refer to the optional step 8 "Adjust The Hole Diameter" for more details.

When the translation is smooth you can insert the M3 bolt into the "knob". Once again the fit should be tight enough to hold the bolt in place by friction. If it is not the case for you, you will need to glue it.

After that you can proceed to the final assembly by placing the base and table together with the spring in between, use the bolt to hold them together and add the rods. Check that the spring is strong enough to push the stage all the way; if it is the case congratulation, your linear stage is finished.

You may add the top hot melt inserts on the top surface depending on your needs. If you plan to use this stage in an assembly and you know which mounting hole you will use it is not necessary to add inserts to all the positions.

For the XY stage you will need the 3D printed parts: 1x "XY stage base", 1x "XY stage table", 1x "XY stage middle" and 2x "knob".

Place the M3 nuts at the extremity of the bolt push it in the hexagonal holes of the "XY stage middle". There are two nuts to insert. Fit should be tight. You can heat the nut a few seconds with a lighter to help the insertion. If the nut does not hold in place by itself you should glue it.

After that place the "XY stage base" and "XY stage middle" together and insert the rods in the holes. Use a rod and a drill to adjust the hole size until the two parts can slide smoothly together (refer to the optional step 8 "Adjust The Hole Diameter" for details). Disassemble the parts and repeat the process with the "XY stage table" and "XY stage middle". You should use a marker to note which side of the "XY stage middle" inserts in the base and which part corresponds to the table as it may not be completely symmetrical anymore after the hole adjustment.

When all the translations are smooth you can insert the M3 bolts into the two "knob" and proceed to the final assembly. Check that the spring is strong enough to push the stage all the way; if it is the case congratulation, your two axis linear stage is finished.

You may add the top hot melt inserts on the top surface depending on your needs. If you plan to use this stage in an assembly and you know which mounting hole you will use it is not necessary to add inserts to all the positions.

For the Z stage you will need the 3D printed parts: 1x "Z stage base", 1x "Z stage table", 1x "Z stage middle" and 1x "knob".

To build the stage add two hot melt inserts to the inner side of the "Z stage base" like in the second picture and insert a M3 nut in the hexagonal hole of the "Z stage middle".

Insert the 61.5mm rods in the "Z stage base" and the 44.5mm rods in the "Z stage table".

Position the "Z stage base" and "Z stage table" together and add the 4x 25.5mm rods. Adjust the hole size with a drill and rod (see optional step 8) until the two parts slide smoothly.

Add the bolt in the "knob" and assemble the "Z stage base" and "Z stage middle" together using the 40mm spring and the "knob".

Place the "Z stage table" on top and fix it by placing the 20mm springs in the top holes of the table and holing it in place with the 2x 25mm flat head screws.

Check that the translation is smooth and the springs force the table down after unscrewing the knob. If so congratulation, your linear stage is finished. You may add the top hot melt inserts according to your needs.

FDM printers can hardly provide the resolution required to produce a perfectly smooth sliding mechanism without any play. For this reason i aimed for all the 2mm rod holes to be slightly tight and you will likely need to adjust it. The best method i could find to obtain a perfect fit consists in using the same 2mm rods (not drill bits), and an electric drill to locally heat the PLA and deform it to the right diameter.

To do that first install all the rods that form your sliding mechanism and test the fit. If you see that one hole is too tight remove only that rod (keep the other ones in position to ensure the two printed parts are hold correctly one related to the other). Mount a long rod on your drill, insert it in the hole and spin it for 15 to 30 seconds. The rod will heat up because of the friction and the PLA will deform. Move the two sliding parts back and forth during the whole process to make sure the "forming" is uniform over the whole mechanism.

If you overheat the part and induce play the only solution is to re-print the parts...