[bakon_boy]

I was talking about your X axis rails. I assumed they were supported? If not, you're going to see a LOT of flex in them. Yes profile rails are far superior. There are some chinese versions available that can be had for maybe double the cost of the round rails. Or, careful Ebay shopping can get them for even less.

Ahh I thought you meant the Z axis. The X axis are supported rails as well as the Y-axis both have that sideways orientation. I played around quite a bit with the ride on orientation but couple things made me change. The main reason was that when I had them on top I either lost a whole bunch of cutting area OR I had to make it that the spindle could go overtop of them (in order to get the second spindle over to the side of the table the first spindle has to go over top). This is scared me because it makes crashing into the rails a possibility which would be terrible. With the current orientation its the best of both worlds in that respect. They are protected from the router and I don't lose any cutting area (actually gain).

I have seen plenty of machines with them installed that way but has anyone had any problems because of it.

[bakon_boy]

Another question for sizing PSU's. I noticed that the voltage output of a torrodial psu drops as more current is drawn from it. My question is when you use that formula to calculate voltage (sqrt(2.5mH)*32=51V should I just get a 48V PSU knowing that under load it might see more like 40V or should I go to a 60V so when under load it see closer to that 50V.

I also noticed that impedance values are +/- 20%. I imagine if anything they actual will be higher than stated so new voltage requirement could be as high as 55V which makes me think maybe a 60V is a better selection.

[louieatienza]

The voltage limit is set by the manufacturer, for the G540, 50V is the absolute limit; typically we'll use PSUs under that for a little safety. As to the impedance values, I'm not sure but you could be right about that.

[bakon_boy]

The voltage limit is set by the manufacturer, for the G540, 50V is the absolute limit; typically we'll use PSUs under that for a little safety. As to the impedance values, I'm not sure but you could be right about that.

Yes for the G540. but I am still planning on using G203V so both are well below the 80V maximum. So with that in mind with a motor that has a 3V rating with 2.5mH +/- 20% would you say play it safe with the 48V or try and get the most out them as possible and for with a 60V?

[louieatienza]

I don't use those, but I think that rack and pinion users are getting between 30-70i/s/s accel rates in Mach3. You might be able to get a bit higher rates due to the higher mechanical advantage.

When you start getting into higher speeds, steppers start to rapidly lose their appeal. Not only do you have to trade velocity for acceleration, you also have to start giving up resolution as you go faster.
I'm currently working (very slowly) on a dual spindle router. I was originally going to use the 570oz motors with a r&p type setup, but have since decided to go with 400w AC servos, which will give high acceleration, high velocity, and high resolution. The downside will be the high cost.

50lbs is probably far more cutting force than you'll encounter with the spindle you'll be using. 30-50lbs is usually a safe estimate.

I was talking about your X axis rails. I assumed they were supported? If not, you're going to see a LOT of flex in them. Yes profile rails are far superior. There are some chinese versions available that can be had for maybe double the cost of the round rails. Or, careful Ebay shopping can get them for even less.

No, you can't daisy chain G540's, but you can use another parallel port to add additional drives and motors, as well as additional inputs and outputs.

A SmoothStepper is another option, since it offers two parallel ports via USB or Ethernet... The other downside with servos are that they can be difficult to tune.

From what I've read, the new Easy Sevos (or step-servos) from Leadshine can have faster response times and higher torque at lower speeds than servos; as well as full torque at a larger speed band. No tuning necessary, and they are also capable of 3000rpm max...

[louieatienza]

Yes for the G540. but I am still planning on using G203V so both are well below the 80V maximum. So with that in mind with a motor that has a 3V rating with 2.5mH +/- 20% would you say play it safe with the 48V or try and get the most out them as possible and for with a 60V?

It depends on the motor. Like I mentioned, the higher end stuff can be pushed harder. I probably wouldn't go max out either, though in reality you can throw as much voltage to a stepper that your drive will allow, as long as you keep everything from melting! You should be able to adjust a 60V PSU down a few volts via trim pot. What you don't want to do is over-current.

I've become a big fan of EdingCNC's USBCNC drive board, and they have a 5-axis version. Their interface is excellent as well as support.

[ger21]

So with that in mind with a motor that has a 3V rating with 2.5mH +/- 20% would you say play it safe with the 48V or try and get the most out them as possible and for with a 60V?

The formula from Gecko, 32 x sqrt (inductance), is intended to determine the maximum voltage. NEMA 23 motors will usually run very hot at this voltage. According to Gecko, increasing the voltage even higher will give little benefit and may damage the motor, if you can't keep it cool.

From everything that I've read over the years, imo, the best motor for your application is probably a 6 amp ±460oz Nema 34.

[bakon_boy]

Anybody have an answer to this?

[vtx1029]

Why dual spindles on a small machine? What cam software are you going to use to determine what spindle is doing what operation? Or are you going to post edit the lines of code to change what spindle does what. Personally I'd overhang your Y axis on both sides so you can access the full cutting area with either spindle.

[bakon_boy]

Why dual spindles on a small machine? What cam software are you going to use to determine what spindle is doing what operation? Or are you going to post edit the lines of code to change what spindle does what. Personally I'd overhang your Y axis on both sides so you can access the full cutting area with either spindle.

The main propose for this machine will be manufacturing kitchen cabinets. That require routing as well as drilling. Instead of changing bits we are going with dual spindle. The g-code should be pretty straight forward so I could change it post but I am hoping to do it will tool presents. Haven't had a lot of the to look in to this but say tools 1-99 will be on the pc and 100-199.

The reason I didn't overhang is that is that I prefer to keep everything inside the footprint if that makes sense.


Sent from my iPhone using Tapatalk - now Free

[vtx1029]

Yea its too bad ATC spindles are so expensive it would be much easier than dual Z's.

[Bob La Londe]

ATCs spindles are expensive but consider the cost of two spindles, two vfds, two sets of Z axis hardware, two sets of wiring, two stepper/servo motors, and two stepper or servo controllers. Then some additional switching hardware, wire or whatever and the exrta time in CAM to make it work. Its still cheaper, but not much.

What I would actually prefer to see is a nice VFD controlled high speed spindle with a quick change tool holder. Something like the TTS system for a Toramch mill with its power draw bar and tool holders. It would be a great compromise. Just setup your machine to stop and go to a convenient tool change position when it hits a tool change command in the code, and then wait for you to press start. I do that all the time with my Hurco mill with its KWIK 200 spindle. I set my tool change macro to lift the spindle to machine zero, middle of x travel and move the table to the rear of the machine. Then I can change the tool quickly. At that point I can either employ the presetup tool tables for premeasured tools or I can zero that tool. I press start, and it starts executing code again.

The two spindle approach I think will need to employ a tool change macro as well. It will swap the Z and the Z^2 (A?) axis, and employ an offset between the position of the two spindles and tool lengths.

[ger21]

ATCs spindles are expensive but consider the cost of two spindles, two vfds, two sets of Z axis hardware, two sets of wiring, two stepper/servo motors, and two stepper or servo controllers. Then some additional switching hardware, wire or whatever and the extra time in CAM to make it work. Its still cheaper, but not much.

Two spindles and all the associated hardware that goes with them is far cheaper than an ATC spindle. That's why I'm building a dual spindle machine.

You don't need two VFD's to run two spindles, just a few relays. A second 2.2Kw spindle is about $200. An extra stepper is $50. Say $100 for the drive. Add $300 for Hiwin or THK's and a screw.
It shouldn't be more than $750 to add a second spindle.

With an ATC spindle, add $100 for each tool holder alone. So if you have a 6 tool ATC, you'll spend more than the second spindle for just the toolholders and the rack to hold them. Then add $3000 for the spindle, and you'll be about $3000 more than adding a second spindle. A little more than "Not Much".

[louieatienza]

Why dual spindles on a small machine? What cam software are you going to use to determine what spindle is doing what operation? Or are you going to post edit the lines of code to change what spindle does what. Personally I'd overhang your Y axis on both sides so you can access the full cutting area with either spindle.

You can just create a separate progran for the second spindle, along with the offset; not too hard. If doing a batch run you can just combine the programs with a text editor, being most kitchen cabinet partitions are the same...

[louieatienza]

ATCs spindles are expensive but consider the cost of two spindles, two vfds, two sets of Z axis hardware, two sets of wiring, two stepper/servo motors, and two stepper or servo controllers. Then some additional switching hardware, wire or whatever and the exrta time in CAM to make it work. Its still cheaper, but not much.

What I would actually prefer to see is a nice VFD controlled high speed spindle with a quick change tool holder. Something like the TTS system for a Toramch mill with its power draw bar and tool holders. It would be a great compromise. Just setup your machine to stop and go to a convenient tool change position when it hits a tool change command in the code, and then wait for you to press start. I do that all the time with my Hurco mill with its KWIK 200 spindle. I set my tool change macro to lift the spindle to machine zero, middle of x travel and move the table to the rear of the machine. Then I can change the tool quickly. At that point I can either employ the presetup tool tables for premeasured tools or I can zero that tool. I press start, and it starts executing code again.

The two spindle approach I think will need to employ a tool change macro as well. It will swap the Z and the Z^2 (A?) axis, and employ an offset between the position of the two spindles and tool lengths.

Just wondering if the Tormach TTS spindle cartridge is capable of RPMs needed for most woodworking. If so that might be an option... As to dual spindles, all you'd have to do is zero each spindle... I'm sure Gerry's tool height macro can be simply modified to zero BOTH spindles.

[bakon_boy]

Been working on the electronic cabinet. I think the $20 computer case is quite a find. Got the control computer mounted in the case and most of the power cables lengthened. Just waiting on a few SATA cables from Ebay.

Attachment 204156

Front Panel

Attachment 204158

Mounted power supply

Attachment 204160

A bunch of fans and motherboard mounted.

Attachment 204162

Back panel. Computer cut-outs done. Waiting for the electronics stuff to arrive to start the motor cut-outs, limit switches etc.

[bakon_boy]

First shipment of electronics arrived. Just missing the drivers, motor cable, and other bit and pieces from eBay.

Motors, BOB, smoothstepper, motor connectors and limit switches.
Attachment 204858

Mounted the power supply. Much heavier than I thought it would be.
Attachment 204856

Hoping to get the BOB and smootherstepper mounted and start programming this weekend.

[bakon_boy]

Been working more on the electronics and making some major headway. Last night function tested all of the motor connections, inputs, and outputs and everything seemed to work. Just waiting for a couple more fans and the main power switch and this should be buttoned up.

The cabinent is a lot more crowded than I hoped which is ok but is a major pain to install because I don't have access to the rear of the BOB or the 5th axis driver so its kind of a puzzle to get everything in.. When planning this I didn't think this was a big deal because once you have everything hooked up should very rarely need access. However, sitting there looking at this last night and I realized that if the fans that are cooling my heat sink ever quit I basically need to diassemble everything to get to them. So I am hoping the fans have another million hours in them.

Heat sink with drivers and relays mounted.
Attachment 207196

x2 120mm fans blowing in series to cool the heat sink. Hopefully this is enough to keep everything cool.
Attachment 207198

Power side with the door open. Nearly complete.
Attachment 207200

Control side, looks like a pretty good rats nest.
Attachment 207204

Close up of the BOB
Attachment 207206

After all the wires are hooked up looks much nicer.
Attachment 207208

Door closed on control side.
Attachment 207210

Door closed on power side.
Attachment 207212

Back of cabinent with all the connectors. Missing some fans and a filter.
Attachment 207202

[mmoe]

I have a dual spindle machine and have not had any problems getting the tool change to work directly out of the CAM software. It's usually pretty easy to get a post processor to output the correct code for a tool change that also takes into account the spindle work offsets. There usually would be no need to do any hand coding or editing later, but of course there are always some CAM packages that are more limited than others in terms of post processor customization. Basically, the tool change code looks like this:


G54 (Head 1 offset)
M31 (activates head 1 relay output and lowers/makes active head)
M03 S15000 (spindle on/spindle speed)
G4 P2 (pause for spindle wind up before continuing)

[bunch of code to cut stuff]

M5 (turns off spindle output and raises/deactivates all currently active heads)
G55 (Head 2 offset)
M32 (activates head 1 relay output and lowers/makes active head)
M03 S15000 (spindle on/spindle speed)
G4 P2 (pause for spindle wind up before continuing)

M5 (turns off spindle output and raises/deactivates all currently active heads)
G56 (offset same as head number two G55, head number one is cutting a specific distance further to the positive X direction, spacing adjustable on my machine)
M33 (activates both head 1 and 2 relays and lowers/makes both heads active simultaneously)
M03 S15000 (spindle on/spindle speed)
G4 P2


The way that I've produced these tool change codes automatically is by using the tool number (usually accessible in many post processors) and adding 30 to it. This creates the correct M code to operate the heads. The offset value is done the same way, by creating an integer by adding 53 to the tool number. If I select tool number "1", the offset will be for head number 1 and head 1 will be lowered. If I select tool number "2" in the CAM software, the offset will be for head 2 and head 2 will be lowered. If I select tool number "3" in the CAM software, the offset will be a separate, but matching offset to head 2, while both heads are lowered and cutting identical parts in duplicate.

In some cases, you have to be more creative to get the code to generate properly, but most post processors have one facility or another that will work. For example, if the post processor allows you to add a tool name, often times that can be used when it doesn't have a bracket or parentheses surrounding it within the variable. You could also just name the tool a specific number to match a needed M code where the post processor doesn't allow for math. There are often a lot of unused features within a post processor that can be accessed for these purposes even though they weren't intended to do so. There will be some CAM software that won't allow for these things to happen, but that probably needs to be taken into account when purchasing CAM software.

[bakon_boy]

Getting close to being finished. Even though I haven't posted in a long time.

After getting some quotes from machine shops to make some aluminum plates for me, I decided to make them out of plywood and then use the CNC to make the aluminum plates with help from a drill press. Overall I think it worked out pretty good.

Attachment 220564

Attachment 220566

Attachment 220568

Attachment 220570

Attachment 220572

Couple videos too.
https://www.youtube.com/watch?v=g3CJB3HYExk

https://www.youtube.com/watch?v=KteNGG2BRDI

I was surprised how much weight was added switching to aluminum. I seem to be able to do 200ipm rapids without any problems, which I am fine with. I would like to go higher not for practical purposes but just for show. If I go any higher than that I seem to start stalling the steppers. Would you say that the steppers are just torquing out or is it possibly resonance issues?

The current most frustrating issue is that when if I have the bolts holding the ball screw nuts to the blocks loose 200 ipm is no problem on both the x and the y axis. Everything sounds smooth. If I even just finger tighten those bolts everything goes to hell. Ballscrews get harder to turn, they sounds bad going one direction (not too bad the other direction), and steppers start stalling at anything over about 20-50 ipm. Any ideas why? I thought it was an alignment thing, but with a dial gauge on the block while I tighten those bolts nothing moves more than a couple thou. Anybody else have any issues like this before???