MIA 3D Printer Micro - Fabrikator Mini II Revamp for Higher Precision and Ease Of Calibration by MIAMicroFlight

Last crawled date: 3 years ago

A 3D printer design I am working on as time permits reusing some of the mechanical parts of a Turnigy Mini II 3D printer.
My very first 3D printers were a couple Fabrikator Mini II, I bought for prototyping quickly small parts. I made a lot of great parts on them, after making some upgrades to improve the precision, but leveling the table on such tiny enclosed machines was always tedious and the hex socket screws used to level the table were not deep enough for the hex key to engage in them, and geting to them inside the enclosure was a task!. So I decided to gut all the components and make them work around my own design.
I still have the other Fabrikator Mini II for nostalgic reasons. I was going to sell them almost new for 1/2 the price, but I really like the original design except for the hard to level and acces the hot end issues.
Bear in mind this is my first 3D printer design "revamp" and a good test of the part quality of my new Anycubic I3 Mega that is making all the 3D printed parts for this revamped project. So far so good!
This started with a logical placement of the given stock mechnical parts with a machine style in the tradition of the very early industrial types of CNC routers and Mills with the work bed Y axis front to back for logical ease of accesing parts and working on the machine, but in miniature. However, once I had the main parts printed and assembled with the extrussion, I began to see some areas that could have been done simpler and since I really like the Anycubic I3 mega, layout, I decided to rearrange the parts and go with a similar layout, thus the new drawing. The base is done in 4 sections, it is a bolt on assembly, the top wth the rail supports part of the upper 3D printed plate, two sides and a bottom. This will double for the Y rail support and be the enclosure for the electronics nice and neat just likle the Anycubic I3.
Nov 11, 2017 - Project Start
Currently, I am printing the Y axis Liner support base, this is taking most of the platform on the Anycubic I3 mega. I printed this with no bottom fill but with a 25% fill for the rest of the part, this was done to make the thickness of t this part honeycomb like, for strength yet lighteness.
The square aluminum extrusion I am using for the frame and some of the 3D printed parts may seem overkill on such a small machine, but I learned long ago that if you are going to build a precision machine you have to start with a solid framework. The T-Slot aluminum extrusion I am using is 1"x1" but one could replace such with a square 1/16 wall alu tube of same outside dimensions. The T-Slot is nice since things can be attached more easily at any given point along its length without having to drill though the tube. One could also use precision square wood made from bass -oak. But the T-slot extrussion offers the best precision and rigidity. There are no micro precision 3D printers on the market, at leat not since the last time I researched it, and since I have the materials and tools, I decided to dive into this project and make it to my own needs.
MIA 3D Printer Micro SPECIFICATION:
High Rigidity and Precision
Logical
Simple
Easy Access
Easy Leveling
Use Aluminum T-Slot Extrusion with 3D Printed Parts
Design around Stock Fabrikator Mini II Mechanics and Electronics
Why I really decided to do this :
Well, I had some T-Slot 1x1" alumium extrusions waiting for a neat project and so I decided to design the structure around these extrusions. The original Fabrikator Mini II is very rigid and is done in anodized blue aluminum enclosure, on some models, so this was the nice part, but acces sto the build table and for maintenance and calibration ? not very user friendly. Otherwise, it is a nice little machine that outputs some fairly decent parts, when calibrated properly. But to make a more precise and easy to acccess and adjust micro 3D printer, capable of printing on same 100x100x100mm working area, I decided to take on this task.
The 3D Printed parts are being printed on an Anycubi I3 Mega 3D printer for precision and right now there is still a few parts that need to be made and tweaked, but it is looking great!. I will post more photos, files, as projects continues.
Nov 12, 2017 - New Cad Layout
New CAD Photo Uploaded. I have made some changes to the base, just to get the item printed and try it for fit, in real time. The idea with the base is to get it done in 3 printed parts, each is small enough to fit on the Anycubic I3, Mega , better if you have a larger printer. The Base "skirt" has provisions for screw mounting via posts part of the skirt that alow the top and bottom to be screwed on. I did this for ease of acces to the base. It also has perforations at the front and at the back for air flow to the electronics which will be installed inside. The "skirt" part of the base is also integral with the front panel, and I did this to establish a solid conplete rectangle support (the "skirt"). This also has a couple side tabs that screw onto the side base posts of the gantry tower. Very similar to the way the Anycubic I3 is done, so no brainer here, except customization of the base for the Fab Mini II guts.
I also finished the upper Z axis support posts, these are floating, meaning they are able to slide on the Alu horizontal upper frame extrussion and allow for side adjustment, for parallelism.
I have most of the framework assembled and waiting on the base "skirt" to finish printing so that I can assemble the base with the Y axis. The Y axis at the top of the base was tested and it moves nice and smooth, but I had to modify the linear sliding rail to clear the belt buckle under it. The top of the base, the one with the integral Y Axis rail supports was printed as one piece, as the stl file shows, but I had a bit of warpage on the ends since the thickness is still dense at M6 or 0.250" thick with infill of 25%, I may do this part in two section, and go with the rail supports as separate pieces over a G10 1/8" thick sheet. Much like I plan on doing the base bottom from G10 as we do not need the thickness for a bottom plate, just a thin cover for the base enclosure. M2 or 1/16" thick Aluminum would be the other option. But I got plenty G10 in various thicknesess so I will probably use that. We'll see once I have the base skirt printed and assembled with the top.
The Z and X axis was also tested and it slides nice and smootth with very little setting of the 3D printed parts.
...More to come...
November 13, 2017 - Real Product Photos
New Real Product Photos uploaded. I had to redo the Z Axis in view that the stock Fabrikator Mini II Belt is too short for the distance of the independent Z axis rods and Blocks. I was going to cut the stock belt to get an exra 1" of length, but I decided not to do this. The new Z Axis block is all in one piece but may flex due to loosing the front bulk as the independent Z blocks have in order to access easier the screws for the Y Axis motor. However, I can alwwas go back to the independent Z Blocs with a longer belt which is faily cheap. I just need to order one that has the same width and teeth spec. Anyway, I wanted to upload real product photos so viewers can see how the actual product is coming along and how the Anycubic I3 Mega printed the parts. First prototype asssembly is always a must, because it allows one to see the physical model and any areas that may need tweaking. It normally takes me 3 attempts to get from concept to finish and tested product.
I did not spend too much time on the electronic board fit, in CAD, but this is going to be a bit challenging fitting it in the smaller base, with easy access to the SD Card and USB slots on the side, as the original Fabrikator Mini II has, but other options were considered.
November 15, 2017 - Heated Bed Platform
The actual build of this revamp design has allowed me to redesign the heated bed better. I am going to make an auxiliary aluminum frame to support the existing Fab II hot plate and this will ride over a G10 thick plate that will mount to the 3D printed part, both for support and insulation from the hot plate. This will also have a larger footprint by 1" around the perimeter of the hot plate so that the leveling hardware can clear the hot end at the very extremes of the build platform, be neatly hidden under it and be easily adjustable. A glass table has been also considered as the Anycubic I3 Has. If I could get a hold a miniature size "Ultrabase" it would be awesome!
November 24, 2017 - Z Axis Boots
I addded the boots that hold the Z axis rods in place over the base blocks. These boots have a glove fit tolerance for the Z rods and have 2 perforations that mate with the base blocks using M4 screws in a self threading manner right into the plastic base to hold them in place.