Build a 3D Printed Suction Mount

This tutorial will show you how to build a suction mount compatible with a variety of printed tools I designed. It includes a phone stand, a camera stand, a vice, various translation stages, or a modular lab holder system.

Except for 5x M3 bolts and a few M3 melt insert, this design relies exclusively on 3D printed parts. It is low cost, versatile, with a variety of attach points adaptable to most purposes, and can easily sustain more than 5 kg in any position.

I use it mostly to fix recording devices (phones and cameras) on the glass windows of gloveboxes, and to quickly secure a vice on a glass table.

However, the final performances of this device heavily depends on the printing quality of the suction cup element. The step 1 of this tutorial is dedicated to this issue and I recommend reading it in details before deciding if you want to build this device.

To build this suction mount, you will need the 3D printed parts available on Thingiverse, Printable and Makerworld (choose any depending on your preferences). The repositories also contain the Solidworks and STEP files for you to modify if you feel so inclined.

Besides the 3D printed part you will need:

1. 5x 10 mm M3 screws
2. 4 to 13 4.2 mm OD, 4 mm long melt inserts: Taobao, Aliexpress, Amazon

The links are only provided for reference, and I do not endorse those products.

Required tools:

1. Allen key / screwdriver
2. Large pliers/vice (for the pin installation)
3. soldering iron (for melt insert installation)

Facultative:

1. Hot air station / heat gun (to melt the surface of the TPU part and improve smoothness)
2. PDMS/Silicone (to cast a thin layer on the suction cup base)

Suction mounts work by forming a vacuum between a flexible "cup" element and a smooth surface. The requirements in terms of mechanical properties are not very restrictive and any type of TPU will work. However, maintaining the vacuum for extended periods of time is challenging with 3D printed parts. There are two key challenges: the printed cup surface roughness and the cup porosity.

Surface roughness depends primarily on the texture of the printing bed. The quality of the first printing layer is also important but is not a difficulty with most modern printers. Textured print beds cannot be used. Similarly, using a layer of glue or PVA or your print bed as a release layer usually introduces a lot of defects and should be avoided. However, TPU adhere so strongly to PI beds that if you print a cup on a smooth PI bed, you risk damaging the bed when taking the cup out. To prevent that, you can freeze the bed and the print before removal. It helps but the method is not guaranteed. The best way is to use a glass print bed. With automatic levelling, it guarantees a smooth surface and relatively easy removal.

Alternatively, the roughness issue can be mitigated by using extra soft TPU (60A to 85A) that can deform to compensate for bumps and groves. It is also possible to use a hot air gun or soldering station to melt the surface of the cup. That process is helpful but difficult to control. Vapor smoothing with DMSO should also work but I did not experiment it.

Whatever method you decide to use, the suction cup part should be printed fully dense with an extremely large number of outer walls (I used 80). Using so many walls guarantees that the small groves associated with the print lines will be parallel to the side of the cup, making the migration of air inside the cup harder. You can also use concentric infill with 100% density, but you also need to set the number of bottom layers to 0. There might be variations depending on the slicer type and version, so make sure to check the first layer of the Gcode.

The second issue is porosity. That problem is easily solved by thoroughly drying your TPU filament and using a slight over-extrusion (102-104%). However over extrusion with highly flexible filament can often cause jamming in the extruder and you should monitor your print.

Both the surface texture and the porosity issues can be solved by casting a thin layer of soft silicon or PDMS on the suction cup. Just place a few drops on a piece of glass or smooth plastic, press the TPU cup on top and let it cure. In my experience, this is a very reliable method and a cup I printed has been holding up for years in my bathroom without falling.

Once you go though the hurdle of printing the suction cup, congratulations, the rest is trivial. Just go to the next step to see the building process.

Besides the suction cup, all the other parts of this mount can be printed in standard 3D filaments. I used PLA+ rather than PLA for the added toughness. However, PETG, ASA, ABS or even PLA will all work. For esthetic reasons, you may want to print the nut and lever in a different color... The STLs are pre-aligned and you can print them as they are. If you use Bambustudio you can can use the 3mf file I provide. Otherwise I recommend 0.2 mm layers, 4 walls and 25% infill. Some parts require supports.

The files are designed with a tolerance of 0.15 mm. Once printed, you can use a vice to hold the screw part and insert the nut. To function properly, the nut and screw should not slide too easily, so a tight fit is normal and intended.

To start the build, place the screw on the suction cup and secure it in place with the two pins. You may use a vice or large pliers to push then into position. They should hold in place by friction.

Place the suction cup and the screw in the bottom casing and add the nut. Turn the nut until it is flush with the top of the screw (the recess is on the bottom side of the nut).

The position where the screw top is flush with the nut corresponds to the "open" position (where the base doesn't adhere). At that point, the screw is pushing the suction cup out of the base to purge all the air during installation and to easily remove when you want to change its place. Keeping the nut in this position, present the lever part and take note of the orientation (you can make a mark). Turn the nut about 45 degrees and use two M3 bolts to fix the lever.

Take the top casing and place it on the assembly while paying attention to align the screw holes. Secure it with 3x M3 bolts and use a soldering iron to install the melt inserts.

There are 12 holes for melt insert, but depending on the tools you want to use, you may only need 4 or 8. If you do not know, I suggest placing 8 inserts on the corners of the outermost and innermost square.

Congratulations! Your suction mount is finished. Before trusting it with any valuable equipment, I recommend fixing it to a window and check how long it sticks for. The strength it holds with, just after you place it, is not a good indicator of how long it will stick. If there are porosity in your suction cup, it will stick extremely firmly at the start, only to fall off after 5 to 10 minutes, as air infiltrates through the cup. On the other hand, a good printed cup can hold a few kilograms for years.

Suction cups are sensitive to dirt and scratches. Keep it in mind when storing your mount.

This suction mount is designed with a variety of attachment points to allow you to fix any tools you may want to design/adapt. However, I also designed a collection of useful tools you may be interested in, including a universal phone holder, a camera base, a vice and a variety of translation/rotation stages for precise positioning. This mount is also compatible with my articulated arm design, you may want to use a few of its ball join links for increased positioning freedom.