Have some questions whilst I assemble my LR2 - your help and guidance will be much appreciated…
No matter what I do I cannot make the gantry seem to run up and down the squared table surface without having some wiggle along the way - is this normal? I haven’t installed the belts yet (that is the next step) so is it simply that once the belts are on it should right itself and should run smoother?
I am a complete newbie to wiring electronics (apart from basic stuff from building my delta printer kits) - I have found some info on wiring for the LR2 but can you please suggest/advise the basics of wiring the steppers, etc. Definitely don’t want to blow up my new Rambo 1.4!
If your table is in fact square and you start the run from a position that is lined up squarely, once the steppers are powered they will run back and forth happily all day without issues. I went through this same experience, and ended up putting runners on my table. As long as the stops are lined up they aren’t required.
Can’t offer a ton on the electronics but just follow the pictures and guides carefully and you’ll be fine. I didn’t have any issues and it sounds like we had similar levels of experience. Good luck
The rambo boards are pretty robust but you should always unplug from power when working on the motor wiring. With steppers, the worst that can happen with a wiring mistake is a nasty buzzing and jerky or no movement. It sounds afwul but doesn’t hurt the motors. Plugging or unplugging a motor while the controller is powered can ruin the stepper diver chip
I’ve installed the belts, and am looking at the wiring. I am really sorry but am just not getting it with the wires. I have 3 bundles, 1 bundle with 2 connections, and the other 2 bundles with 3 connections each.
Am I connecting the two Z steppers with the same 3 connection bundle? And the same again for the two Y steppers? If so, with an X table width of 1.2m, is that possible?
When I purchased the LR2 Kit from V1, I bought an extra set of Series Wiring Kit (1 bundle of 2 connections, and 2 bundles of 3 connections) so have these available also if need be.
I read somewhere on here that when testing to see if the steppers have been connected correctly, that it is best for the belts not to be fitted. Is that a must? I really don’t want to remove the belts and reattach all over again!
Ok, brain has started to work better and understand the wiring - I was overcomplicating things
I noticed that one end of the Y Plates seems to curl in towards the table more than the other. I must have screwed one of the bolts tighter than another? but can’t work out. Is there an obvious fix that you came across?
Also, quite a bit of force has to be used to move the gantry along the belts (by hand) - is that normal? I imagine there needs to be a relative amount of force to keep it all running steady, but is there such a thing as too much? I don’t want to burn out the steppers!
This project is awesome, loving every minute of it. Thanks!!
It is really hard to judge what “a lot of force” is. And if you gave me a number, I probably wouldn’t have a good frame of reference.
Are you talking about the pipe axis or the wheel axis? The wheel axis moves more smoothly when the motors are precisely driving both sides. The pipe axis should be pretty smooth. If it isn’t, it is probably overtightened.
Sorry for not replying sooner to your message, have been away for a few days.
Regarding axis, I mean both the pipe and wheel. I know from my 3d print delta I have the belts as taught as possible, but they are tightened by hand only, no screw or zip-tie. As you said, impossible to explain the amount of force, particularly for a newbie like me.
On another note, I got the wiring series done. As you said very straight forward as it turned out.
My next 3 questions are relating to connections to my Rambo 1.4…
I changed the US plug socket out for an EU plug. Now I need to cut the other end that needs to connect to the board to power it. Does anyone with a Rambo 1.4 (or experience of it) have a diagram or photograph as to where I connect them directly?
(I see the reprap page and the UltiMachine page but I have one single AC Adaptor from V1, and on the mentioned pages I see 4 wires going into the board)
By looking at the power connection area on the board, looks as though I need to purchase some form of connector??
Regarding question 1 does it matter if I cut the end before or after that secondary feature about 100mm back from the connection end of the power cable (it is between the power block and the connector)
Thank you for your help and apologies for the basic questions! I am loving the learning curve!
Answering question #1: You need to wire power and ground to both the logic connections and to the motors connections. You can see those connections labeled in this photo. As for connecting the wires, your Rambo board should have come with a terminal block connector that plugs into the board like this one. For my wiring I jumpered between the two power and to grounds like is done is this photo, but I kept the jumpers much tighter to the connector so that the board would fit into this case.
Hi Robert,
That is so helpful thank you.
Unfortunately in the V1 kit I bought, there was no terminal block included. I will have to buy one.
What gauge wire should I use to jumper between the power and the logic connections? And do I simply jam in the jumpers with the initial motor connections and then connect those jumpers to the logic section?
Thanks again
I also purchased from V1, and the terminal block was included. It was in a separate package with some other parts. If you cannot find it, then I’d contact Ryan.
The logic circuit does not draw much power, so I suggest wiring it up the way it was show in the picture with the power coming into the motors connection and the jumper going to the logic connection. Personally I soldered the jumper to the incoming wire, and I tinned the other end of the jumper. I soldered the two wires together because when there are two wires coming into a terminal connection, the screw often bites onto the thicker wire leaving a thinner wire loose. I used 16 gauge solid core wire for my jumper. This is overkill on size given the low current draw of the logic and fans. I used solid core copper so I could pre-bend the jumper to just fit into the right slots while still being tight to the terminal block. Note I’m just a hobbyist when it comes electronics, so while I thought things out, I have no idea if this is the “right” way I should have done the jumper…or if there is a better way.
I had another look through the box and discovered the terminal block, I don’t know how I missed it the first time around.
Have cut off the end connection of the AC adaptor which reveals the red and white, so will connect the red to + and white to -, and then run the jumpers across to the logic section. What you say about soldering and tinning sounds like an excellent plan, so I will do the same.
There is a LOT of controversy regarding using soldered wires in a screw-down terminal.
I do a lot of aircraft panel wiring and also work for the Portland Community College Aviation department. The aviation technicians are taught to NOT use solder on crimping or screw-clamp connections. This due to the vibration and flexing causing wire to break just “outside” the crimp or clamping connection. Virtually all aviation and military connectors are not soldered.
As I understand it, the crimp or screw connection is actually better without the solder. That’s what I’ve been using in the glider panels I re-wire and since I have stopped using soldered wire ends I have not seen any connection come loose, or wires breaking.
YMMV, but I’d skip the soldering step, if you’re using a screw-clamp type connector.
The way they work best is to crimp on a ferrule at the end of the wire. E3D sends their heater wires crimped this way and they work great in the screw terminals.
But let’s be honest, we aren’t going to the moon here and soldered or loose wires will probably be fine.
Using Repetier-Host, Y and X working great. But the Z axis will only lift one side or the other, never both. I have tried swapping each connection of the series and retried. That includes switching 180 degrees at the Z connection on the Rambo 1.4 I have. I have the Z plugged into the Z connection adjacent to the X and Y slots (not the further one along)
The result is that both motors are working, just never together
Any ideas please? Thanks in advance
PS I have noticed whilst dealing with the Z axis that the couplers end up quite extended, is that ok? ( consequence whilst I was trying to work out what was going on with the Zs.) Do I need to adjust them in any way? They are approx 1mm below the base of the XZ Main piece. But I have noticed some people have them lower, should I have done that??
I have a Rambo 1.4 with ‘out-of’the-box’ firmware flashed.
I got the Z direction resolved
However, I think I have overstretched one of the couplers.
Whilst trying to figure out the Z problem, I must have permanently stretched one of the couplers a bit. So, one of them has larger gaps than the other. Both leadscrews appear to be touching the motor shafts. Do you think this is a problem and I need to purchase a new coupler or you think a matter of a few mms of gap between the ‘gills’ of the coupler is not such a big deal? Sorry, total newbie question I know!
So far, and it is of course early days, the 3 directions appear to be moving really nicely and crisply.
Yes, the gantry does indeed fall when powered off. Is there an alternative to that?
I think that in due course I will probably add the endstops to the project - I realised, having come from 3d printers which use them, that I missed them today when I went too far and overstretched the downwards Z.
I would be fine with that. As long as the shaft is touching, it should be at a consistent height. You might want to order a pack of couplers on the slow boat to have one ready if they ever stretch more or break.
No, that’s how it is supposed to work. You just need to jog close to the bottom before powering off the motors. It is annoying, but it really helps aligns the Z when you start and not falling is a sign that your Z has too much resistance for the motors.
You can add them. It is pretty easy, but they do not stop motion when triggered. They are ignored unless you are homing.
The dual endstop versions have the sole purpose of adjusting each motor to square the gantry consistently. I don’t have endstops on mine, because I am sure I can start square enough without them on a 5 foot gantry. After start, the motors move in lockstep and it stays square.
I should add that on a 3D printer, the bed is the ground truth, so endstops are critical. But in CNC, the workpiece is the ground truth and endstops don’t know where the workpiece is. So it is logical to drop them on a CNC, but need them in printers.
