Prusa i3 Laser Cut Frame and Braces

by sgraber, published

Prusa i3 Laser Cut Frame and Braces by sgraber Jan 6, 2013
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Prusa i3 Laser Cut Frame and Braces by sgraber is licensed under the GNU - GPL license.

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If you need one cut, the folks over at http://tricklaser.com/ can cut one for you.

This "thing" is a stub for the laser cut files for the Prusa i3 printer frame for use with wood, acrylic, and other thin material. Published under GPL v3, same as the Prusa i3.

Grab the files from my Github repository: https://github.com/sgraber/Prusa3_LC

I have provided three file types: dxf, eps, and pdf.


More photos are found on my photostream at Flickr: http://www.flickr.com/photos/sbgraber/8351936888/in/photostream/

Please note: my braces, while they look similar to Twelvepro's, were designed independently and were mostly done by the time Twelvepro released their files. The major differences between my braces and their design is:

  • mine are 7" wide whereas theirs is only 5" wide
  • the Prusa frame is stock with the exception of increasing the hole sizes for M3 screws and adding slots and holes for the brace nut traps and tabs
  • one brace supports RAMPS 1.4, RAMBo, and Sanguinololu electronics and the other one (will) support RUMBA and Printrboard in the next git commit
  • only two additional parts added to the bill of materials
  • ability to use all stock plastic parts from Prusa's git repository
  • sized for 6mm double-faced melamine board and 1/4" acrylic
  • no laser cut files for z-axis motor mounts and smooth rod

The goal of this revision is to allow people to use frame material that is less rigid than the 6mm aluminum, which is specified for the Single Sheet Frame Prusa i3 Printer (http://reprap.org/wiki/Prusa_i3#Single_Sheet_Frame) and have it laser cut instead of water jet cut. Laser cutters are more accessible for people either at their local makerspace or at local laser cutting businesses. Laser cut material is also less expensive and people can source different frame colors and materials, such as 5mm birch plywood, 6mm double-faced melamine, and 1/4" acrylic.

To achieve this goal, two angular braces are designed and added to the bill of materials and the stock Prusa i3 Single Sheet Frame is slightly modified to accept these braces. A major goal of this revision is to keep the Prusa i3 frame as stock as possible so that people can continue to print and use Josef Prusa's i3 parts from his Github repository: https://github.com/josefprusa/Prusa3/tree/jo-final In this release, the frame dimensions were not changed at all. The only additional items added to the i3 bill of materials are the two laser cut braces and six 25mm/1-inch M3/6-32 SAE screws and washers.

This frame was designed for use with 6mm-thick material. Thicknesses less than or greater than 6mm will require the brace tab lengths to be decreased/increased and the square tab-accepting holes in the Prusa i3 frame to be decreased/increased accordingly. I have found that oversizing the tab-accepting holes by 0.2mm works but each laser cutter is slightly different and may require adjustments different than this.

Changed and New Parts

Changes to the stock Prusa i3 frame:

  • Screw hole size increased from 2.5mm to 3.5mm to allow for either 3mm or 6-32 SAE screws
  • Added square tab holes for braces
  • Increased bottom 8mm circular holes to 16mm oblong holes to allow pre-wired motor connectors to fit through
  • Moved RAMPS 1.4 mounting holes to the braces
  • Added "i3" text to top of frame
  • removed two heat sink for extruder motor as wood / acrylic makes for poor heat sink material
  • removed y-alignment tool and associated holes in frame as the new braces take care of this

New braces (2) :

  • Measure 370mm tall x 178mm wide (7" x 14.6")
  • Oblong holes in brace bottom allow for pre-wired motor (and other) connectors to fit through
  • Mounting holes for both RAMPS 1.4 and RAMBo one one brace (Sanguinololu and RUMBA holes on the other brace forthtcoming)
  • 80mm x 8.8mm slot in bottom ties into the top-back y-axis threaded rod using four washers and nuts and an extended y-axis threaded rod
  • Nut traps accept either M3 or 6-32 hardware (Nyloc nuts, 25mm / 1 inch screws)


2013-01-08: Latest frame version from Josef Prusa makes the following changes:

  • Removes three LM8UU y-carriage plastic parts. Y-carriage updated so that LM8UU's mount directly to the underside of the y-carriage using zipties.
  • Four ziptie holes are added along the base of the frame for managing wires
  • Two rectangular motor mounts are removed
  • Removed Printrboard mount holes

How to obtain a laser cut frame

I have provided three file types for people to use when laser cutting: dxf, eps, and pdf. Your local makerspace or laser cutting business should be able to utilize one of these three file formats to cut your frame and braces for you.

If you would prefer to purchase one of these frames and associated braces online, I will soon provide these parts on Ebay along with my printed parts, which conform to the latest versions found in the https://github.com/josefprusa/Prusa3/tree/jo-final/ branch. This way you can source most of what you need from one place: http://myworld.ebay.com/sbgraber

I worked with the guys at SeeMeCNC during development of this frame revision and they are also providing the frame for purchase from their website: http://shop.seemecnc.com/ These guys are great to work with and I highly recommend them and their products.



  • Frame (1)
  • Brace (2)
  • M3 / 6-32 SAE screw, 25mm / 1-inch long (6)
  • M3 / 6-32 SAE washers (6)
  • M3 / 6-32 SAE nut / nyloc (6)

Slide the tabbed braces into the frame. Slide a washer onto an M3/6-32 SAE screw and insert the screw into each nut trap hole. Use either a standard or nyloc M3/6-32 SAE nut and screw tight.

Assemble the remainder of the printer per the instructions in Prusa's repository: https://github.com/josefprusa/Prusa3/blob/master/doc/manual.txt

Open Source Hardware STL courtesy: http://www.thingiverse.com/thing:27097

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It says in the description that M3 bolts and fasteners are used for the braces. This is only partly true.
The holes in the main plate are M3, but the nut trap and "screw trap" on the braces are for M5.
No big deal though as you can just drill out the correct hole in the main plate. Just wanted to let people know, so they can change this before actually using the laser cutter. Otherwise great model, thanks for that!

I was looking through the git commits and noticed that the Printrboard mounting holes were removed at one point. Just curious why that was done?

I want to modify your file because I find a 8mm thickness wood.
Do you have a CAD file with the cotation ?
I use solidworks and when I import the file "frame-6mm-colored-lines.dxf", there no cotation and for example round whole are in several line.

So it's not easy to modify it .

Thanks for help.

I have a question. Will the parts from Prusa i3 Rework be ok with this frame? http://reprap.org/wiki/Prusa_i3_Rework_Bill_of_materials

Yes, rework parts fit fine as that is what I am using.

The rework uses 10mm threaded rods. Does the frame need to be modified somehow for them to fit?

Can someone answer this please? I'm looking to build one of these using the rework parts... I'm really unclear as to what rods to buy..

Thank you for your reply. Where did you get the parts? Are there ok? http://www.thingiverse.com/thing:119616
Someone said they were of by 1mm.

Prusa i3 Rework

Lots of things will cause a variance of 1mm. Its not the design but the printer. I bought mine on ebay. Takes about 34 hours to print that many parts

I'd like to propose a tweak to this.

I bought a 16" by 24" ( 406mm x 610mm) piece of acrylic, thinking I had measured it correctly (since you didn't specify total dimensions anywhere).

I was off by about an inch or two.

Resizing the two support wings horizontally by about -10mm each allowed the whole set to fit on one 16x24" piece of acrylic. This is ideal since that equates to much less waste and you can get 6 sets out of 1 4x8 foot sheet of acryllic. This is an easy adjustment in inkscape, but you need to be careful not to resize the hole pattern.

Could you please upload this? I'd be interested.

I've uploaded my modifications to this design to Github


I've submitted the changes as a pull request to the original author.

Hello. Files body no longer there?
Wanted to find like my printer, but with no result :(

Link to Github is in the Description.

These are fantastic, thank you! One question for you as I'm new to using these types of designs. How much 6mm acrylic am I going to need for this? I don't see measurements anywhere on the pdfs..

Are brackets really necessary when using a 6mm or more frame?
I am planning on using a 8mm acrylic frame - without brackets - has anyone tried it? and if so, should I be using a different design (less holes?)

Even the Aluminum single frame needs support but doesn't have it. We can add support to it but I wish Josef would stop making half ass designs and on his blog he said he designed the i3 for aesthetics not for functionality.

They are needed, otherwise I wouldn't have added them. ;)

Hi ,It's so amazing. But The https://github.com/josefprusa/Prusa3/tree/jo-finalhttps://github.com/josefprusa/... is can't be opened. Is the plastic parts in fourth picture same with this picture http://www.flickr.com/photos/sbgraber/8426169640/in/photostream/lightbox/?http://www.flickr.com/photos/s...
And https://github.com/josefprusa/Prusa3/blob/master/box_frame/sample_stls/single_plate_htd3_lm8uu/x-end.stlhttps://github.com/josefprusa/... is different form the fourth picture.where can I find STL file which is same with fourth picture ? Thank tou so much!

/jo-final was factored out some time ago from the Prusa3 git repo. Any of the parts in the single_plate or box_frame Prusa3 repo folders can be used with this frame.

Thank you so much! I find the file in single_plate, and I used OpenSCAD to open them file successfully.

Great design

Where can I find the DXF laser cutting file?

Can you Change the Bed? With 4 LM8UU? On the Lasercut Version it Crashes on one side to the cable ties.

Hi I got this frame but the only thing i realized i don't see how the wing set the the main frame or how the back part of the y frame is attached? I only see the front part. SO if you can t ell me what size screws or what ever in need to do to get this frame set up proper.

I really like this style frame now i just need to set it up :)


It uses 1" #6-32 screws with #6 nyloc nuts and #6 washers, 6 of each.

Thank but do you happen to know what the metric size is for the back screws are?

From the readme on git: "The only additional items added to the i3 bill of materials are the two laser cut braces and six 25mm/1-inch M3/6-32 SAE screws and washers."

I had a doubt which may seem pretty silly. When I open these .dxf files in a .dxf reader and use the measure tool, it shows dimensions much larger than what they should be. For example it shows one side of the frame as more than 9000mm!!. I am sure I am missing something. Can any one help please.


Where can I find the DXF laser cutting file?

All DXFs are saved in mm. Make sure you're importing using mm and not inches.

Thanks ..:)..Apologies for the late Kudos..

Hello! Great design ;)

There is a way to obtain a dxf ready for a 9mm MDF? Or I have to edit myself?

You will need to edit it yourself. This frame is strictly for 6mm material.

thank you aniway ;)

Looking really forward to building this. Do you have a link to the exact printed parts/bom used to complete a printer with this frame? I just don't want to complete something which is not compatible in the end. Thanks - sorry, I'm on a low budget and can't afford to spend more than I need to.

Thanks for this great design!

Hi it seems your github us broken as I can't download anything at the moment

You clicked on the ZIP button, right? It worked fine for me.

I bought this kit from SeeMeCNC. Is there any way to clean the burn marks off of the wood or do I have to paint it? And does the campfire smell ever go away?

When you say "clean the burn marks off of the wood" do you mean off the edges or from the surface of the melamine? You can't clean it off the edge. If you want to paint the edges, the easiest way is to leave the masking on and spray paint the edges. When dry, remove the masking.

Yes, the smell goes away. Most of the smell is on the masking and when removed the bulk of the smell will go away. It may take a day or two of airing out as well.

I figured it out. I started to take the package apart and found that the burn marks were on the masking tape layer and it was clean white board underneath. The smell has lessened since I unpacked it.

Hi unfortunately the Prusa3WOOD-v4.dxf also would not open in Acad2010. Could someone on this page try and open the DXF in sgabers github in AutoCad 2010 and email it to me at my user name at gmail dot com. I've got all the parts now to make up the Prusa i3 apart from the frame... And I can't afford shipment from the USA.
I much prefer sgraber's design to josef's design. So could someone help me here?

The PDF didn't work? Opening it in inkscape and exporting it as an AutoCAD compatible file didn't work?

Yup that finally worked and my laser cutting company can finally open a dxf in acad 2010. This trick might be useful for others whose laser cutting company only use acad2010 as well.

Hi Sgraber, I'd much prefer your design than Josef Prusa's so it you could put an acad 2010 compatible dxf in your github listing (Clearly identified) that would be great. I have looked at the ceemecee site and the killer for me is the postage to Europe, hence my request to have an acad 2010 file to give the laser cutting company here in Cluj Romania. (Who only laser cut metal, never wood) so I will be getting 6mm Aluminum ( I think that's how its spelt in the USA). If you don't have Acad 2010 could someone else on this page provide one? It really would be appreciated.

Did this frame file not work? "Prusa3WOOD-v4.dxf" from https://github.com/josefprusa/Prusa3/tree/master/single_plate/src/frame/6mmhttps://github.com/josefprusa/....

FWIW Autocad export says it exported fine. Worst case, pull it into Inkscape and save as a PDF.

hey Sgraber, unfortunately my laser cutting company say that they cannot open the dxf files in AutoCad 2010. Can you open this file in acad 2010 or can you please save a copy in this format. This will help me get my frame laser cut.

Thanks! It's actually a concept I'm developing in conjunction with http://SeeMeCNC.comSeeMeCNC.com. Once the design is locked down better and we have a bit of printing on it, we'll release the source files so others can enjoy!

What's your thoughts so far on its design?

Hey sgraber, do you have any idea how long the wait will be for the ace new i3LC files?


Should be pretty soon! We're just working out the x-motor and x-idler at this point.

Less of Printed Parts.. And the Design can used with minimal Mods on a CNC Machine. With 2 square tubes, the Design can stack 3-4 Printers.

seemecnc was in USA... I in Europe/Germany.. Many thinks i want, was in the USA. But when i buy something, i have VAT and Postage.

One thing, i think you can change.


For the Printingbed , Can you make longholes (correct?) for better Calibrate of the Printingbed?

Example what i mean:


So the Printingbed can be Calibrated. In your Design it was not possible.

No need for print bed calibration as the holes in the y-carriage line up perfectly with the rods: http://www.flickr.com/photos/sbgraber/8462274430/in/set-72157632677580692http://www.flickr.com/photos/s...

Constraining the threaded rod is not good as it can (and will) induce z-wobble.

Ok.. Thanks... Wait now for the files...

This is a great little frame. I'm just finally acquiring the correct plastic parts for it, as most Prusa i3 sellers are selling the box-frame parts and I picked up the wrong ones — twice. As a RepRap newbie I expected frames to follow a standard. Now that I know more that sounds funny! Nevertheless I'm adding notes to the published (EtherCalc) BOM to point out the different requirements for this particular frame, both previous and current versions.

One suggestion I have to improve this frame is to move the Mega/RAMPS mounting holes a little higher up. The Arduino Mega's USB port is on the bottom of the unit and most USB cables have long rigid connectors which just barely fit in the vertical region available. A little more space would eliminate some of the kink in these cables.

How much higher (mm?) should I move the RAMPS mounting holes?

That's the one thing I do with all of my Ebay sales - point out exactly which repo I've pulled parts from and which i3 variant I'm selling. FYI I sell the single_plate i3 parts specifically and they're 100% compatible with this frame.

I love it. :) Oh, I haven't been on Thingiverse in about a week now and I come back and I absolutely hate this new format they chose. Frankly the moron who decided they needed to go to a mobile format can kiss my butt. Just sayin'.

Made some minor updates based on an update by Josef Prusa today. See changelog above.

What is the printing volume?

Print volume has not changed. IIRC it's 8"x8"x8".

Thanks for making it easier to build i3. Is it possible to provide template file in SVG/EPS format? I want to get the laser cut frame from Formulor and it accepts only EPS or SVG file. Thanks

I have added an EPS and PDF to the repository. Also, within the next two days I will offer the laser cut frame, braces, and plastic parts on my Ebay store. Also, you can currently purchase the frame + braces cut from SeeMeCNC. Links to both are found above.