THE BUILD IDEA:
I am looking to build a C-beam machine with little to no modifications. My reasons are to dip my toe in the CNC waters, with an anticipation of diving in head first into the pool. I will be basing (copying... for now) my design on Mark Carew's C-beam http://openbuilds.com/threads/c-beam%E2%84%A2-machine-plate-maker.2349/page-2. I have ordered a C-Beam kit with the optional nema 23 and as for now I am not planing to make any modifications out side of the electronics.
I am going to use an Arduino Uno (clone) (I have one and got a good deal on a new one with link below) Arduino - ArduinoBoardUno
With a Protoneer shield ( again clone I believe) Protoneer.co.nz | Electronic Prototyping Specialists or Arduino CNC Shield V3.51 - GRBL v0.9 compatible - Uses Pololu Drivers
With Pololu DRV8825 stepper motor drivers (with heat sink) Pololu - DRV8825 Stepper Motor Driver Carrier, High Current
Here is the bundle I ordered (out of Kansas might be Chinese parts but a good price) CNC Shield V3 Expansion Board + 4 X StepStick DRV8825 + UNO R3 For Arduino
Have not bought or really looked at power sources, but I'm open to suggestions. For the moment I will be theoretically repurposing an old computer 12v power source. After looking at it, we will see if I can get it to work, some help here might be needed. (see questions below)
I have not yet ordered a power supply. I will be using an old ATX (computer PSU). I can get 12v with 8A of current. This should be able to get the motors running but have been advised to get a min of 24v.
I already own a copy of TurboCAD deluxe (way more than required for 2D drawings) (a great affordable CAD program) for my vectored drawings TurboCAD Deluxe 2016
For a CAM software I am really interested in ChiliPeppr http://chilipeppr.com/grbl but see myself dishing out some loot for a Vectric product, Cut2D, Vcarve or beyond. Products - Cut2D
How I got here:
I have always been a woodworker and now currently work in the house building trade, this is because it pays the bills. I would love to hang out in my shop all day and make cool furniture, but in this day and age of throw away society people tend to go to IKEA and oak express and these guys can sell a table for less than I can buy the wood to build the thing. I have made some one off pieces that are really nice but are also very labor intensive. I already design in CAD thanks to a great high school teacher for planting the seed and years of self education. I have always wished that my hands and tools could be as accurate as my drawings. I was in one of my self educating sessions trying to look up some help for my CAD software and I ran across a video from Legacy CNC woodworking (won't post a link because they are a possible competitor to OB, I don't know) (they do have an awesome collection of educational videos on both their site and YouTube) the video was how to take a CAD drawings form the same software I use to a CNC machine and I was hooked, I was ready shell out the multi-thousands of dollars to buy a CNC machine. Considering I don't have multi-thousands of dollars I started looking at different options and came across OpenBuilds about a six months ago. My interest grew and so did my list of questions. Instead of bombarding different threads with hypothetical realities. I needed a tangible and interactive reality and so here we are. This is also my first “blog” ( if this is even a blog) of any sort and I hope that not only myself will gain knowledge but others as well. Mark did an awesome job on the C-Beam and his build blog, I will document my reproduction build and would like to expand on my choice of electronics in my blog.
So my C-Beam bundle will be here tomorrow! The Build will begin just as soon as that box gets to my door. In the mean time I have been getting some of the electronics going.
I modified my ATX PSU. All -2 common wires (black) soldered together. All yellow (12v), all orange (3.3v) and all red -1 (5.5v) soldered together. 1 black and the red unused wires were connected with an 8ohm, 25W resistor (pull up resistor to get full 12v from yellow wires, with out this I was only getting ~10v). The other unused black wire and the sole green wire are the power switch. All other wires disregarded ( low current negative voltage wires and "power ok"(LED) wires). This is just temporary but it is what I have on hand. I have been advised in the discussions that steppers like their voltage.
With this PSU connected and the Arduino powered via USB (could not do it without Arduino powered) I adjusted DRV8825 driver current limit to 2.2A with Vref voltage set to 1.1v.
Link to a good video aboout setting current limit for the DRV8825
I flashed GRBL to the Arduino via IDE with instructions from Compiling Grbl · grbl/grbl Wiki · GitHub. I did have to update my Arduino IDE version but had no other complications.
I downloaded Universal G-code sender GitHub - winder/Universal-G-Code-Sender: A Java based GRBL compatible cross-platform G-Code sender. to get some motors moving when I get them.
I got my bundle today! I got right to work (after the UPS guy got here after i got off work). I got it all together (well almost read on). I left the motors off while I play with the electronics. Here are some pics of my build, for a comprehensive build video Mark's C-beam build is what you are looking for.
So here in pretty much step #1 I had a wheel missing from one of the mini v-wheel kits. I was a little grumpy that this happen so quickly, but I have now ironed out the wrinkles in my undies and understand mistakes happen so c'est la vie.
Here is the missing wheel all the bearings, shims and nut were there.
X beam with "x-z" plate:
Z beam with "x-z" plate
X and Z beams connected
Z with lead screw
Z and X with lead screw
Y plate and beam
Y lead screw
Post with frame
To get the frame all square was a bit challenging. First of all the 500mm beams were not all the same but there were 2 sets that were the same. When I first put it together I had two different sizes for the inside beams (Y mounts). Took some things apart and got 2 that were the same size on the inside. Then the cast corners have little nubs on the back side of them and the 6 corners (2 in front and 1 rear, each side) holding the outside beams these nubs were giving me problems getting it all tight and flush. Quick trip to the grinder and there were no more nubs. This however made the 10mm screws to long, I was able to use some 8mm screws from the pile and make the remaining screws work in other spots so not that big of a deal. Nubs gone, matching inside beams and I got everything all tightened up. I flipped the frame over and use a carpenters trick to square it up, measure from corner to corner and if the measurements are the same it is square ( this will work for a rectangle). With a little nudging I got it all square. Yea me.
And here she is in all her glory
Total build time was ~5hrs
Overall the bundle pack was great, everything was well packed and labeled. The M5 screws were all real tight on my allen wrenches, I used a ratcheting screw driver with a allen bit to get things tight because I could put some pressure into the screw and keep the bit seated. In some of the tight spots where my screw driver could not fit I struggled to really get things tight as the allen would want to strip the head of the M5 screws. This could be my wrench set I don't know. The nubs on the cast corners were a bit annoying but only felt I had to remove them from one side of 6 of them. A few extra 8mm/10mm screws would be nice, you get exactly what is needed (minus a wheel ). These are just nit picky things and I do really think it is a great bundle. Thank you Mark and thank you OpenBuilds.
Ah the motors you ask
Here in my Frankenstein PSU hooked up the the Arduino and sheild.
And a Nema23 hooked up to the Y axis
I got the universal G-code sender to spin it around a couple of times. Will be playing with this more in the days to come stay tuned.
So I have spent some time cleaning up the electronics.
PSU less Frankensteinish
Soldered some header pins on to the nema23's to connect to 4 wire jumpers, they were female to female so I needed pins on the steppers.
I found the coil pairs that were blue/yellow and green/red. Before I soldered them I found what direction this set up would rotate when I jogged in the +/- directions in universal g-code sender(UGS). Then I rotated the lead screws and figured what direction they needed to turn to go in the +/- directions on each of the axises. The Z and X axises were the same (as pictured above) and the Y was the opposite ( swapped the blue/yellow order).
All three steppers hooked up with the PSU
Then I attached the motors and everything work just the way it should. I set the steppers at 1/32 steps. Set the GRBL step/mm to 800. 1.8 degree stepper motors, 8mm lead screw ( travels 8mm per revolution) and 1/32 steps comes out to ((360/1.8)/8)*32=800. I played around with the UGS and everything looked great. I did a quick search of the internet and found a simple g-code and attached a marker to the spindle mount and this was the out come.
My first product from my C-beam. Not to shabby if i do say so my self. Like the beer boxes taped to the Y plate to smooth it out?
So this was all last night and tonight I wanted to draw something in CAD and convert it to g- code and send it to the machine. Easy, right? Not as easy as I thought it was going to be. The drawing was easy enough, I didn't know what to draw so I just drew (not imported or traced, drew) the Open Builds cog and saved as a DXF file. I will attach the DXF file if anyone wants it. The problems for me came when I was trying to convert it to g-code. I was looking for freeware and I run a Linux operating system on my computer, I run my TurboCAD out of a Windows virtual machine so I was trying all sorts of things Chillipeppr, sketchUCAM the free trial of cut2D from Vetrics and could for the life of me get none of these to work without hours of research. Finally I found SheetCam Welcome to SheetCam and it worked.
With just a little playing around I got this
Now I just need a router and some bits and the sky is the limit. More coming soon.
The CNC shield is rated up to 36v and drivers up to 45v would I be better off getting a 24v or 36v supply? This has been discussed in the discussions(go figure) and what I get out of it so far is to be safe I should get a 24v PSU but if the CNC shield is a quality part it should handle the max rating of 36v.
Sugestions on affordabble CAM software? Who's good and Who's not? I will probably be looking at a dedicated laptop that runs windows just to make my life easier for software compatibility.
Over all thoughts, am I doing this right(biting finger nails)?
Thanks for coming along.
Gargoile reproduction C-Beam™ Machine - Plate Maker
A stock C-Beam with a CNC shield with DRV8825's
- Build License:
- CC - Attribution - CC BY