This page contains 3D-models and manuals on 3D-printing. I developed these methods and models for use in our own laboratory, for our Ultimaker2 printers, so they work well for us. I hope they will be useful for other people too. But before use, you need to evaluate the safety and usefullness for your environment, which may differ from mine. The risk is all yours. I can not be held responsible for any problems these methods or models would cause. All files should be virus-free, as we have a central antivirus running continuously on these servers. However, I recommend you verify every file after downloading, just to be sure. Redistribution is allowed, as long as you follow the license terms (see at the bottom of this page).


The Salt Method: wiping the glass bed of a 3D-printer with *salt water* improves bonding of PLA

This manual describes a new way to get a very good bonding of PLA to the heated glass bed of a 3D-printer, by treating that build-plate with salt water first. Hence the name "the salt method". When hot, the bond is very strong, but after cooling down, models pop off without any force at all. Works excellent with PLA, but does not work at all with ABS. This manual is published under a CC BY-SA license.

File: bonding_pla_with_salt_water_v20160713.pdf (PDF - 2.2 MB)

thin mist of salt on build plate


Improved and more gentle "atomic method" to clean 3D-printer nozzles

The "atomic method" is a well known technique to clean the inside of the nozzle of a 3D-printer. Although it works great to remove dirt, it also has a few risks due to the brutal pulling.

This improved atomic method works equally well, but it is a lot more gentle, without any risk of causing damage to the printer. Basically, it replaces the brutal pulling by gentle turning and wiggling, and deeper cooling. The manual is published under a CC BY-SA license.

File: improved_atomic_method_v20160713.pdf (PDF - 2.7MB)

improved atomic method


Compact Low-friction UM2 Spool Holder

This is a very compact low-friction spool holder for the Ultimaker2 3D-printer. It fits one standard spool of 750gr (Ultimaker, colorFabb, ICE, etc.), and features a standard 608 skater wheel bearing. It is useful when there is limited space available behind the printer, or if you prefer frictionless movement.

The ZIP-file contains the STL-files to print, a JPG-image of each part, the original design files (in RSDOC-format - DesignSpark Mechanical v1.0), and a text-file with more info and instructions. This design is published under a CC BY-SA license.

File: (ZIP-file, ca. 4MB)

um2 spool holder


Anti-unwind filament clamp

This clamp prevents the filament from undesired unwinding and from falling off the spools. If used while printing, no locking screws should be used, so the clamp can freely slide over the edge of the spool. The clamp then prevents the filament from falling off the spool sideways, which could cause it to get mangled up. This clamp also makes it much easier to manually unwind a bit of filament, and straighten it, to prevent underextrusion on UM2 printers. Lastly, this clamp can be used to fix the filament while in storage, so it does not unwind, fall off, or get stuck under itself.

The sliding action around the edge of the spool only works for colorFabb and identical spools. Ultimaker and ICE spools do have diagonal spokes that prevent the clamp from sliding. The clamping-function while in storage however, also works for Ultimaker (non-NFC) and ICE spools.

Test the sliding function carefully before use, to make sure it does not get locked-up at some points around the edge!

The zip-file contains the original RSDOC-designs, STL-files to print, several JPG-images, and a text-file with more info. The design is published under a CC BY-SA license.

File: (ZIP-file - 2.6MB)

anti unwind clamp


Character set for 3D-printing

This character set is designed to create small text labels in a 3D-print, for 3D-printers with a standard nozzle of 0.4mm. Character height is 3.5mm (caps height), character width is mostly 2.0mm, and line-width is 0.5mm. When using transparent or translucent filaments, it is also possible to create legible watermarks in the model, as shown in this picture.

You can print the testplates to evaluate how 3D-text would look on your printer: raised text, recessed text, positive watermarks (=solid text surrounded by voids inside model), negative watermarks (text as voids inside model), etc.

The zip-file contains the character sets in RSDOC-fileformat, testplates in STL-fileformat for tryouts, and JPG-images showing what each design and testplate looks like. Be sure to read the txt-file for more info and instructions on use. This design is published under a CC BY-SA license.

File: (ZIP-file, 4.3MB)

character set for 3d printing

Recently Jason Chall turned some characters of this set into a real font-file (thanks). See here on Github or Thingiverse for the font-files (TTF, EOT, SVG). (Links open in new windows):


Improved horseshoe clips for bowden tube

The standard horseshoe clip to lock the bowden tube, is perfect for systems that do not require frequent disassembling. But if you want to do regular nozzle cleanings (="atomic pulls"), this new clip gives a better grip: you can easily take it off and slide it on again. Its base dimensions are the same as the original clips.

This ZIP-file contains the STL-file to print, a JPG-image, and the original design file (RSDOC-format - DesignSpark Mechanical v1.0). This model is published under a CC BY-SA license.

File: (ZIP-file - 109 kB)

horseshoe clip


Improved bowden tube clamps - "Snake clamps"

These clamps for the bowden tube - "snake clamps" - have a very loose fit, so they do not risk choking the bowden tube, and do not cause extra filament friction.

The ZIP-file contains the STL-file to print, plus several JPG-images and the original design files (RSDOC-format - DesignSpark Mechanical v1.0). Published under a CC BY-SA license.

File: (ZIP-file - 1.5Mb)

snake clamp