Free 4+5 axis CAM software

I got an idea and am currently implementing it.
It's a very simple 4 (and 5) axis CAM software to generate G-Code from STL models.

The problem

Well,  I have an affordable 4 axis CNC milling machine. The 4th axis "A" is commonly a rotational axis along Y or X.
But aparently all free software you can get only does 3 axis milling.
The only affordable software I that claims to support 4 axis milling was DeskProto. A fine piece of software and using it with the 4th axis works very well but it only does 3 Axis milling using X,A,Z and keeping Y stationary.
All "real" 4 axis software costs an arm and a leg. Any 5 axis software I could find is completely and utterly out of every hobbyists budget.

The idea

Now what I'm implementing won't work for every type of geometry.
I'm trying to but there will always be cases that don't fit my algorithm.
The idea is as follows:

1. Run along the A axis from 0 to 360 and along the Y axis, determine the location of the surface (classic pseudo-4-axis milling up to now)
2. Then determine the surface normal at that collision point.
3. Now calculate the inverse kinematic required to turn the part until the surface normal of that collision point points straight up.
4. Determine if this new orientation creates collisions of the tool with other parts of the part or the machine, is outside the movement ranges of the axis or otherwise impossible.
5. If it is impossible or if there is a cave beneth the surface, find the start and end of the region that has this property, put a plane through these 2 points that is normal to the A axis and do classic 3 axis milling in these planes.

Why this strategy?

The idea of following the surface normal is that this works like cutting along a contour. You get a surface without any visible steps.

The problems

Dents in the surface that can only be reached from certain directions are one problem. The fallback strategy of 3 axis milling takes care of many such cases but cannot work for all cases.

Optimizing the collision detection for finding the surface is much more difficult then in 3 axis milling since you cannot partition your model in advance to only test the triangles that actually can be below the cutter.

I haven't yet thought of any proper algorithms to deal with the fact that the tool has a shape.
Currently it assumes a ball cutter of diameter 0 that can cut with the side just as well as with the tip.

The details of the collision detection of tool and collet with the part are still not clear.

As you see, I need a lot of help with thinking about the proper algorithms, implementing them correctly and a ton of testing.

• Executable alpha version

• Sourcecode 
• 4th+5th axis I'm thinking about 
• Aparently SmoothStepper can control 6 axis it's not well documented, has no optical isolators and no galvanic isolation of it's 5V like my current, cheap 4 axis board has.
• USB control board (can't use it. Doesn't work with MACH3)

"R. P. M." 3D printer with serious CNC mill

Tim Rastall on Google+ showed me an interesting project today. This is a beta of a combined 3D printer and desktop CNC mill. Future upgrades for a 4 th axis, laser 3D scanner,… are planned.

R.P.M. Rapid Prototyping Mill ( 3D Printer / CNC Mill )

Context

There have been many attempts to mount small Dremel, Proxxon and other hand tools to 3D printers for small milling jobs. Usually these suffer from the low mechanical stability of 3D printers compared to heavy CNC mills, the high runout of the mounted hand tools and the low mechanical
strength of the axis and axis stepper motors.

Description

This one is different. It uses a water cooled, heavy spindle with a dedicated VFD. Just like a conventional “desktop” CNC mill. The frame looks very sturdy and employs ball screws. It looks more like portal style desktop CNC reshaped into a cube. The Z axis is done RepRap “Darwin” or BitsFromBytes “RepMan” style. On these 3D printers it is overconstrained and introduces the well known “Z wobble” because 4 cheap, threaded rods are employed that are never really parallel or straight. This design uses 4 precision ball screws. So it may work out and allow for the (for a CNC mill) very large Z travel and support the very heavy tool.

Analysis and outlook

I am finding a combination of 3D printing (clean, no storage of blanks), CNC milling (very high precision, diverse materials and tools) and resin casting (diverse material properties, easy small-scale production) to be one of the most interesting fields of research In hobby machines.
As for myself this could be an ideal tool if it would employ metric parts (for easy repair) and the performance in 3D printing and in medium duty CNC milling was known. My own CNC6040 is very limited in it’s Z travel and very long and wide. This one could be small enough to be transported to Hacker meets and –conferences with a car. (Much too heavy to carry a long in a train. 70lbs=30Kg)

• R.P.M. Rapid Prototyping Mill ( 3D Printer / CNC Mill )
• Kickstarter 
• Announcement
• Preproduction model on YouTube

Cage for BMPCC and GH2

I'm currently designing a cage for the Black Magic Pocket Cinema Camera.
But since the camera won't be shipped before July, I'm testing my basic idea with a GH2 first.

Let's start with the requirements:

• small
• follow the form of the camera
• handheld operation, meaning I can stil grab the camera and not have to attach handles to the cage.
• GH2: access to the battery door (not for BMPCC since it can be powered via 12V and even charge the battery while at it)
• Access all connectors, buttons on top and the full back side.

Mark I

Originally I thought about a conventional design like this one and just leave a larger gab on the right side to slip my hand between camera and cage.
The result looks like this:

 This looks nice in theory but has one important flaw.
Because both cameras are tiny, my hand extends a significant way below the camera.

Mark II

So I started to look around and found this cool design.

 I liked the way it put the right side forward.
I disliked the space below the camera as it adds bulk to the cage.

So now I'm changing my design to put the right side forward and allow a hand to grip the camera.
The result is this:

Now this may be easy to grip but...it's in the way when you want to grip the lens from below to change focus or zoom.
Turns out it is quite hard to design a cage that does not get in the way when the camera is to be used handheld, gripping the actual camera body.

CCC Freiburg visits RaumZeitLabor Mannheim

Last weekend the CCCfr Hackspace visited the RaumZeitLabor Hackerspace in Mannheim.
Smaller then the ShackSpace in Stuttgart, we visited before, but wich much more food. ;)
We made us 3 CCCfr T-Shirts using the cool cutting plotter and shirt-press they had to offer and I found the time to drill and solder the PCB I made.
(Originally wanted to drill it on the CNC but I didn't have the right collets to mount the tiny drills.)

• RaumZeitLabor
• CCCfr
• Shackspace

Milling stamps

I'm currently collecting information regarding milling my own stamps on the CNC machine.
The main inspiration is to make some Hackerspace Passport -stamps for CCCfr.

Material

You can get stamp rubber easily.
I thought about deep freezing it but a friend suggested against it and to cut deep with a real sharp bit to get large shavings.

Tool

Aparently an engraving cutter seems to work fine.
Conneticut uses a 1/32"=0.8mm one FFM a 1mm one.

Speed

FFM: 16K RPM and 200mm/s
Conneticut: 6 ipm = 2.5mm/s ???? 

Depth

Both use 2 passes. 
FFM: delta-Z=-0.75mm depth=-1.5mm
Conneticut: delta-Z=0.75mm  depth=0.060" = 1.5mm

• Connecticut-hackerspace
• Frankfurt(M) Hackerspace about it 

My first PCB

My first (hopefully) working, etched PCB.
Made in CCCfr last night.
This time the problem was not the (stored warm and brightly lit) PCB from the store but that my acid simply cooled down.
I didn't have access to a heated machine this time, so I used a 10eur kit and hot water.
We tried to warm it up again using hot air from a distance and later a large hot water tub but it just didn't work again.
Maybe it was already saturated.

Mobile Fräs-Kreissäge-Stichsäge -Tisch

Lately I've been playing a lot with my CNC and woodworking.
Gaining experience in what cutters work up to what depth, what spindle speed burns rather then cuts the wood, how fast I can go, how to mount the parts properly and what tollerances I have to calculate with due to the wood bending, vibrating and flexing.

So here is my next project:
I'm designed myself a portable table that I can mount

1. my large circular saw (using 2 flat bars),
2. my cheap router (using 2 round rods) and 
3. my jigsaw (using 4 bolts).

As you can see, apart from the jigsaw, non of these tools are equipped to be mounted below a table.

Having a CNC, I'm planning not only give them

• precise mounting points but also 
• pocket out the shape of these tools on the underside of the table and 
• provide a bedstop that has precise stops every 10mm, starting at 0mm from the middle of the blade/cutter. ...and use an engraving bit to 
• actually label these stops as well as a number of distances and angles on the table
• and label heights on the bedstop-slider (for the router)

I'm not sure I can pull this off.
For once the table is quite large compared to the working size of my CNC and I have no experience in mouting anything flat yet.
I'll have to cut provisional holes. Use these to mount it onto the CNC. Then use the precise holes to mount it while cleaning up the provisional holes.
I'll also have to think about a sacrificial plate below this part, so I don't hit the CNC's bed when drilling all the way through.
I'll also have to have an easy to center on origin location in case MACH3 crashes, takes the current coordinates with it and I have to find my origin again to resume the program.

 

 IF I get this done, the design files will of cause be released as CC-BY . The mounting holes are very specific to these 3 tools but can easily be adapted to other ones.