Big Disclaimer: the CNC described below is not working. It is incomplete and being actively built since October 2017. If you want to help please contact the mailing list and say so at hasadna at googlegroups.com and see status at BigCNC2017
We also got a mini cnc at http://telavivmakers.org/index.php/Mini_CNC
The CNC is professionally built from large aluminum profiles custom-cut to size, as well as some CNC machined parts. It has brushless servos with encoders on each axis with matching drives (400W for X and Y, 200W with brake for Z). The spindle is a 2kW water-cooled beast with a standard CNC collet. Motion is on accurate linear slides and driven by precision ballscrews.
More info (wiring diagram etc) in google drive
brushless servo motors with encoders on each axis. each has a matching drive (controller module). X, Y have 400W motors, Samsung model CSM-04BB2ANT3. the drive module is CSDJ Plus series, specifically model CSDJ-04BX2.
Z axis, on the other hand, has a 200W motor that also has a built-in brake, Samsung model CSM-02BB1ABT3. the drive module is CSDJ series (not CSDJ-Plus! that's important and probably the problem, see below). Specifically it's model CSDJ-02BX1. it looks like the "BX2' suffix means the 'plus' version and 'BX1' means the older, non-plus version.
A few things that were discussed about the wiring. All the drivers and controller card will all sit in a computer like box. There will not be a central connector (as is now), but the connections will be split as follows: two connectors for each motor (one for the motor one for the encoder), a connector the z break, a connector for the spindle, a connector for each limit switch. That is a total of 14 connectors. This configuration will help troubleshooting because it will allow us to isolate problems (i.e. reconnect motors to different drivers). We made a very crude sketch for the computer like controller box (just so we can get the dimensions of the box). The minimum dimensions that we need are 40cmx50c,x25cm. We need to find a box that meets these minimum dimensions. These are the absolute bare minimum dimensions so bigger is better. I turned our little paper sketch into a sketchup. The images are just to display general layout, just to give you a sense of the design. The sketch is by no means accurate, the connector types and the parallel breakout board are absolutely wrong, this is just to get a sense of layout.
currently thinking of making the motor and encoder connectors on the box the same type as those on the motor. this means the cables we'll build are "extension cables": with a male connector on one side and a female of the same type on the other side. this keeps things simple - one to one wiring, which means easy checking and less room for error (no need for table to look up which pin here goes to which pin there).
spindle controller: 14cmx20cmx15cm x,y an z drivers (size of each): 6cmx16cmx20cm
jr got some of the cat6 flex cable from haifa
for the encoders we need shielded 8 conductor, multi-strand (meaning not solid copper), ideally 24 AWG or thicker for each strand. I thought of getting flexible cat6 network cable such as
Go to http://www.ateksensor.com/ there, under the accessories tab you can see EP-8 cable. This is the information I have, more information is writen on the cables that are at TAMI. The cables are 8x0.34mm on each starnd. these cables are left overs that I have from linear scale and encoders I installed on Press brake machines (Same web site Magnetic Linear scale\Rotary Encoders tabs) and they are very good and the diameter is good for this job. I don't trust the cat-6 cable for a job like that they are not ment for the mechanical work the cable I had brought are from a higher quality and if needed you can check LAPP CABLE web site for the cable you want and I will ask their agent for a price offer, I have a good discount and they are the best cables manufacturer in the world. http://products.lappgroup.com/online-catalogue.html
- F_monster_connector = V_motor
- a_monster_connector = W_motor
Software called Smartjog, it's the software that was designed specifically to configure this type of drive modules. You can set all the drive module's parameters (there are at least 100 of those), such as various closed-loop control parameters, I/O pin configuration and various features tuning. note that this Smartjog is not actually supposed to be needed during regular CNC opration, just for tuning (which is unfortunately essential before anything works). "managed to get Smartjog 3.0 :) it took registering to the Korean RSAutomation site, with heavy use of google translate... also discovered that the "corrupted" messages we have been getting when downloading stuff from their site, do not happen on internet explorer - it does not mean the files were removed as we thought!<br> anyway, I'm not certain now that this SW will help, but it does warrant a try."
source search tami list for "CNC update, and a googling quest!" (dropbox folder >> "hey did you see that")
A table to hold the cnc is under way, made of Tslot aka 8020. This design File:Table.odt uses a whopping 53m of Tslot...
- wire the limit switches to their respective control board (X, Y and Z - 6 limit switches). they should be wired to pins 4 and 5 ("P-OT", "N-OT") on the big connectors of the respective drives. enable those inputs through Smartjog, test if they work (also via Smartjog, the "digital monitor" section).
- wire the limit switches to the indexer board and connect to mach-3. We will use a single parallel port pin due to pin shortage (port has 5 input pins, we need 2 for each axis, i.e. total of 6). in order not to short the switches to one another, so the servo drives still have individual indications, we'll use diodes when shorting them to the one parallel port pin.
- the Z axis motor has a brake, that works on 24V. it is currently hard-wired to the 24V PSU. ideally, it should be connected through a relay controlled by the Z-axis servo drive (the drive has a specific output to control a brake, but it's low power - i.e. an external relay is required).
- test water connections and pump and gantry for leakage. seal as needed.
- continue tuning the servos (when connected to the CNC) for better performance. Cation - incorrect tuning can lead to dramatic, dangerous and out of control machine movement.
- find a better location for the electronics box (better: re-do the electronics box - but that's better left for upgrade work after things are already working)
- get a proper computer for the CNC, instead of the inconvenient laptop. It must have a physical parallel port and serial port (either natively or as an expansion PCI card). It doesn't need to be very fast but it should be decent. put it on the bottom shelf of the table and wire it to the CNC. install windows (XP or 7), Smartjog, Mach3. dual-boot with linux is also possible (for LinuxCNC instead of Mach3).
- configure Mach3: set axes properties, acceleration, etc.
- temperature sensor on the outgoing water from the spindle.
- make table
- Z-axis was fixed
- There was a wiring problem of the Z-axis that might have done damage to the servo driver.
- servo driver was replaced (new, same board)
Guy & co brought over an almost-ready CNC machine he's been building with two friends, on-and-off for the last two years, as a loan for the purpose of getting fresh minds and hands working on it and completing it. If we get this beast up and running, we'll have a major addition to our arsenal!