CN milled catapult

Ever since seeing this little 3D-printed catapult, i knew i had to build a better one. so i designed a bigger and more powerfull one in aluminium.

i used Fusion 360's adaptive clearing to remove the bulk of material, then fiunished of the pieces with contouring rounds.

Here, the parts are laid out for the assembly:

The spring assembly was constructed by layers of 1mm plywood, later knitted around, so that they are still able to slide, but not separate

Of course, i had to use a 3D-printed wrench to assemble it:

The arm was riveted to the main axle:

And here it is, in all it's glory besides the smaller 3D- printed catapult, and the printer who printed the small one.

Milling boxes in fixtures

As Koka Nikoladze had the need to machine some holes in some electronic enclosures, we produced some jigs to repetedly mounting and machining of these boxes.

For Bernt Isak's project, The Cosmos, we made a similar jig, also for cutting out por't for the Arduino's interface.

3D milling aluminium and stainless steel

This weekend i held courses in Fusion 360 at Bitraf. We started of with a course aimed for people without any 3D modelling experience on friday, then went trough some of the more advanced functions on saturday, before moving on to the CAM function and 3D printing on sunday.

On saturday i lectured about assembly in fusion, and the difference between bodies and components, and how to structure the file when building an assembly with moving parts. The case for this weekend was this machinist vise, as we then could use the model when we were milling on sunday.

After modelling the vise, we modelled a test case, 60x60x100 with some random topografy for testing out Fusion CAM's adaptive clearing. As we now had a 3D model of the vise, we could now easly activate collision detection, aswell as grabbing the necesary geometry for mounting the vise to our machine.

As this weekends goal was to experiment with 3D milling, we also tried some different finishing strategies. For aluminium, what worked best where a 6mm singleflute ballmill. Above is a rendered image of the vice, with the finishing toolpath projected on to it using gimp.

The machining process leaves a mess, but since i where using adaptive clearing, it's a uniform mess. All the chips are uniform, since the tool cut the material with a constant load.

I did several tests with different stepdown and stepover. For each test, i let one side be finished, while the other side still had the surface from the roughing pass.

I also machined a 50x50x50 block of stainless steel, this was the result:

This is the toolpath for the steel block. The model was produced by warping a hexagon along an the center axis. As the material was stainless steel, the stepdown was kept low at 0.2mm, but the feedrate high at 1600 mm/min.

The three samples sitting at my desk after a long weekend. i have now aquired the knowledge needed for producing my first injection mold.

Welding aluminium strucures

This was a quick test of assembling aluminium parts.

As one can see in the lower left corner of this structure, the crossbrace, is intersecting through the sideplates. The hole i milled for the sidebraces has extended radiuses so that they can be filled with weld. i Used TIG for this one, that left a super clean, nice weld. After welding, i milled it away, to leave a flat and nice surface.

CNC milled suitcase base

A frind of mine was tired of hauling her heavy suitcase around town, with the small wheels getting stuck everywhere. I made her the solution: a big, thick aluminium plate with huge wheels! 

I used the shell function in Autodesk Fusion 360, together with the web function to remove as much material as possible without compromising on rigidity.

Concrete casting workshop

Yesterday i and Christina Lewis held a concrete casting at Bitraf.
The workshop was meant to be a collective tryout of concrete as material for both art and technology.
We used a thin, low viscosity concrete, intended for use as garage floors.


We did two rounds of castings, in the second round, we added colour in the concrete. The color was a challenge in it self, as adding any substance to the concrete, alters its properties. The one i ended up using, is a pigment in powder form, normaly used for painting chalk walls

For the big candle holder shown at the intro, i milled a mold from building insulation using a 10mm milling bit for removing the bulk of the material, then finishing it up with the 6mm long ball nose.


For the small project that we did over the weekend, using a drill mounted spiral mixer in a bucket where sufficient. For the molds, we used the already mentioned machined foam block, as well as cut bottles, coke cans, crumbled paper cups, and 3d printed molds.

The 3D printed molds where especially interesting, as the low viscosity concrete capture every minute details from the print.

More results from the workshop:

 If you want to try this out yourself, have a lookout for the next workshop at Bitraf's meetup.

Progressing with the screwdriver case

Here is the latest progression on the screwdriver set. Now that i had made one functional prototype of the drawer, the time had come to produce five of the new improved versions.

After generating toolpaths, the parts where milled from plywood and aluminium. The plywood parts where to be milled from both sides, so three wooden dowels where used to ensure that the material lined up from both sides.

Then, once i had five aluminium frames, and five wooden trays, i had to begin drilling the holes for the small brass screws that hold the frame in place. As much as i enjoy operating the CNC machines, there are something special about forming material by hand. Therefore, grabbed my toolbox, and began the process of marking, drilling and countersinking the holes.

After ensuring that the screws did infact fit in the aluminium frames, i mounted the frames to the wood. Using one of my favourite tools, a brass hammer i made my self some time ago, i hammered the frames onto the wooden trays.

Then using another of my selfmade tools, the small parallel clamp, i secured the two pieces together while i predrilled the hole for the screws. Then, i mounted the piece on a small board with a welding clamp, and inserted the threee screws.

As i had not used Bitrafs lasercutter for quite a while, i decided to produce a temporary rack to store the drawers in when i am not working on them. After some thinking, i came up with a quick design in Fusion 360. I took roughly half an hour to cut.

Thats it for now, the next thing i will have to do to finish this project, is to lasercut the wooden inserts for the aluminium frames. Then i will need to cut the final wood cabinet in wich the drawers will sit.

Assembling giant vacuum wall

Months ago i agreed on designing and manufacture a 2100x2500 vacuum wall for Norwegian artist pushwagner´s photo studio.

After producing the technical drawings, the contract was signed, and the product taken into production at Fellesverkstedet

Below are som photos from the production of the vacuum wall.

The vacuumwall must be adjustable. Therefore, mechanical valves where added in form of PE slides.

As a consequence of this, the vall became very thick, and several hundred screws had to be used to keep it from imploding from the underpressure.

This is one of the two halves making up the vacuum wall under assembly.

Here, the two halves of the vacuum table stands ready for delivery and mounting at the customers photo studio:

Autodesk Fusion 360

Yesterday, i and Christian Anker from bitraf spent all day produsing parts using Autodesk Fusion 360's CAM module. We produced the toolpaths on my macbook air, then seamlesly beamed them over to the CNC machine using Dropbox.

The more we learn about production technology, the more we can reduce the turnaround time from concept to reality. For the case of the two copper pieces below, that time ended up at 43 minutes.

Before the copper parts where made, prototypes where made in aluminium. The 3D milling where done at 25mm/sek, with a 1/8 inch ballnose mill.

This assembly is the hammer parts of Koka nicoladze´s new instrument; the solenoid drummer.

As we did further adventures into CNC milling with the shopbot, Christian anker decided he wanted to produce the build platform for his huge part for his 3D printer.

As it must be perfectly flat, it had to be facemilled. We decided to do this with this 32 mm milling bit.

This is the finished part rigth after milling:

Since teaching Christian to mill aluminium with the shopbot CNC machine, he has produced a number of parts for his 3D printer:

Holddown

I prefer to use lasercut wood washers to mount the material on the CNC, aswell as keeping the piece from moving under cutting.

This part were cut from 5mm polyethylene, a very soft material. Therefor, it had to be secured well before cutting.

The washer are cut to spec, so that they fit exactly in the slot.

This part needed to be chamfered around the outer perimeter. To allow this, it had to be secured with a number of washers and screws. Itwas not possible to avoid collision with the washers on the thin parts, so these where hold down with wood washers, while the rest of the part where secured with steel washers.

In this example, i was making a table, and the legs where to be chamfered from both sides. To acomplish this, i cut a jig for the part from some scrap wood. As this jig where cut by the machine itself, i can now position the part perfectly in the machine each time.

Testing out 3D milling in Fusion 360 once more

Today i did some more testing of Fusion 360`s CAM module.

I made a sample 100 X 100 X 50 body, then made a  T-spline plane ontop of it. I then gave it some random topography to work with.

After boundary filling , the part is ready for Toolpath generation!

I intended to run the first files in foam, so i ramped up the feedrate to 3000mm/min @ 15000 RPM.

I used 10mm two flute HSS tools from GARR for this job, a ballnose for the topography, then a flat end for cutting out the part.

The results where good! At 2,5 mm stepover, the toolpaths are clearly visible.

I continued to use the same file for testing in wood. This was made using only adaptive clearing with a HSS 1FL6 from norswiss.