Upgraded the CNC :)

[Carl Fisher]

The stock size was 500mm x 500mm with a cutting envelope of roughly 300mm x 300mm. The stock machine is sitting inside the new 1M x 1M framework to compare the size.

I moved over all of the mechanical components today and the new cutting envelope should be right around 800mm x 800mm which will be a nice change. Just waiting on the longer belting and some various bits and pieces to wire it all up again with the longer rails.

I also moved the z-axis stepper back to give enough clearance to the spindle which also gave me a gear driven belt drive which should increase the speed of my z-axis.

The rabbit hole just keeps getting deeper

 

[ehpoole]

Carl,

Out of curiosity, since one of these years I hope to do something similar, what have your expenses been to date on these two projects? I've been curious as to what some of the DIY solutions are presently running.

But most of all, thank you for sharing your experiences with everyone.

 

[Carl Fisher]

Cost is one of those things you turn a blind eye to at some point in the process Since this was a learning curve for me I've now identified things I over spent on the first time and would definitely correct if I had to go back and do it again.

Simple ballpark pricing, you can get out the door up and running with a handful of decent upgrades including a larger footprint, real cutting spindle and a few others for around $1200 give or take excluding software. Take out the upgrades and you could honestly be cutting with a dremel type spindle and the smaller footprint for about $700.

I'm probably into mine for about $1500 right now as I over-bought on the electronics and have since gone back and replaced the controller/drivers with a different unit to simplify my life. You learn things along the way that make you look back and scratch your head wondering why you didn't know that the first time around. I'm planning to attach the controller to a Raspberry Pi and run the entire unit over the network instead of having to physically plug my laptop in every time I want to run a job.

So right now, I'm setup like this:
ShapeOko 2 hardware kit expanded to 1M x 1M footprint
600W PWM variable speed spindle
Z-Axis belt drive relocation
ACME lead screw on the Z-Axis
Probotix NEMA23 260 oz in stepper motors (overbought)
TinyG USB based controller board (replaced the probotix parallel port breakout board and stepper drivers)
(future) Raspberry Pi 2 to stream gcode to the controller from a remote machine
(future) 4th axis rotary once I decide on how I want this to be built

For the software I have ViaCAD Pro for any real modeling I need to do. Mostly I just use Inkscape (free) for 2D work.
For CAM I'm using either jsCut or MakerCAM depending on my mood and how complex the piece is that I want to cut. Both are free and web based.

 

[KenOfCary]

I just pre-ordered a Raspberry PI 2 from MakerShop. Impulse buy, not sure what I'm going to do with it, but it looked too neat to pass up. Quad processors in a 5" footprint.

 

[Carl Fisher]

There's a bunch of boards out now that are great to look at. Raspberry Pi, Beagle Bone, ODROID-C1, Intel Edison, etc...

The Pi 2 has been certified to run the new Windows 10 which is free as well so that's kinda neat. The ODROID looks to be the most powerful of the batch to the point where you could even use it as a desktop replacement.

 

[kg5000]

Wow Carl! That is going to be a great machine when you're done. I just super-sized my MakeMZBot-inspired three axis machine to a cut area of 52 x 52 and am still working out the kinks.

I am running a cheap Chinese TB6560 "Blue board" controller that I have hacked/upgraded to actually work. It's good most of the time but I'm sure it's responsible for some of my machine's inaccuracies. I have been looking at the SmoothieBoard x3 and the Paucatt Azteeg X5 as an upgrade controller. I run 300 oz-in NEMA 23 steppers that are rated to draw up to 2.5 amps each so the SmoothieBoard's drivers are a bit weak. The Azteeg x5 runs the same Smoothie software but with uprated drivers.

http://www.panucatt.com/azteeg_X5_mini_reprap_3d_printer_controller_p/ax5mini.htm
http://smoothieware.org/smoothieboard

Have you ever looked at SmoothieBoard? If so was there anything that shy'd you away from it?

 

[Carl Fisher]

Kenny, have you looked at something like an Arduino and a trio of DRV8825 stepper drivers? Not sure what you're using for control software but this you would flash the Arduino with with grbl firmware and you could use either ChiliPeppr or universal gcode sender. ChiliPepper is actually very flushed out and capable control software that is being extended almost daily.

 

[kg5000]

SmoothieBoard's software is a port of GRBL which is the basis of TinyG also. The big difference is Smoothie is running a 120 MHz 32 bit processor and 128 MB RAM (Arduino is 16 MHz with 8 KB RAM). You also don't need a sender with Smoothie. The Smoothie board looks like a USB storage device. You copy the NC file from your desktop/laptop to the board and then send a command to "play" the file. There's also some control GUIs out there that allow monitoring and controlling the board.

At the moment I'm using LinuxCNC on an old dual core Athlon computer attached to the "blue board".

The drivers you mention are rated at 2 amps which are probably fine with my 2.5 amp steppers. I'm a bit concerned using drivers that have a lower current rating than the stepper rating. I have a plan sometime to hook up an ammeter inline with the power supply to see what the total current draw is while driving all three steppers.

 

[Carl Fisher]

From what I understand, especially with the non-commercial grade motors that we use, it takes a LOT to actually pull 2.5A out of these steppers. Usually you turn down the current to prevent overheating, skipping/stuttering, etc... I do understand the desire for headroom though

I saw that you could dump .nc files right to the Smoothie, but I actually like to have more control over the process and see the progress. Something about black box processing of the files without a visual bothers me I am kinda curious how you deal with things like homing and z-axis height settings and such on the Smoothie.

 

[kg5000]

On the black box nature of Smoothie I hear you. I thought the same thing. I also wondered how you would do simple things like home without switches, touch-off, etc. I like the continuous feedback I get from the LinuxCNC AXIS GUI.

On a separate point I read on the CamBam forum that someone was having accuracy issues. I struggle with consistent accuracy, too. Through discussions over these it was discovered the guy's acceleration was too low. They recommended a 10x ratio of max acceleration to max velocity. What settings do you use for these with your Shapeoko?

 

[Carl Fisher]

Good question and if I hadn't already decommissioned the linux box I had been using to run my probotix board I'd be happy to tell you. I'm going to have to go through all of that again and re-learn the TinyG's limits. They have some unique way of doing acceleration that is supposed to be quite a bit more accurate.

Per the Wiki

• Constant jerk acceleration planning (3rd order S curves) for smooth and fast motion transitions
• Very smooth step pulse generation using phase-optimized fractional-step DDA running at 50 Khz with very low jitter

Accuracy and missed steps can also come down to feed rate of the job and also current settings on the stepper drivers.