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It makes more sense looking at the cad screen.
Like I say it might just be me. All the machine I have worked on always have the x axis as the rail and they all home , the ones that do home anyway, at the bottom left and some of them home at both sides left and right in they have two carraiges. I am getting used to it, I just have to remember thats it not a profiling machine:confused:
Ian
Jazzcnc,
I dont know about Mach but USBCNC can be configured for turning.
Ian
I decided that I wanted to see the display on my inverter so that I could get a basic idea of the spindle speed.
I removed the front cover from the inverter and found that the display box could be removed. As the photo below shows tha display box is connected by a 10 way ribbon cable.
Attachment 4818
I made and fitted a new cable, 10 way flat ribbon ran inside some shielding then covered in heatshrink.
Attachment 4819
Cut out the box lid and fitted the display unit.
Attachment 4820
Fitted the speed control pot and an emergency stop button and connected everything up.
Attachment 4822Attachment 4821
Power on and test.
Attachment 4823
All seems ok.
Regards
Ian
I like to see my VFD screen but not for speed.?
I have it set to show current being drawn this shows me the load on spindle this way I can see when the tool is getting worn. Also good for gage to show material hardness, esp usefull with shity ALi that has soft or hard spots.! . . Also tells me If I'm being greedy on the DOC.!
Everything Jazz just said... I almost invariably leave mine reading current. Especially on the lathe as there it's actually possible to hit the current limit, though I don't cut that fast often :naughty:
I mounted my VFD on the ceiling above the lathe so it's easy to read and accessible which is handy when thread-cutting.
How long is the ribbon cable? Good to see that the signals made it that far.
I might well change the display to current later on. At the moment I am still taking it easy with depth of cut and feed speeds till I get used to what I can get away with.
Jazz, I know what you mean about Ali. You can hear the change in the tone of the cutter when you get a change in the material. We also get it alot when cutting mild steel on the laser at work. The cut quality will be really good then it will go crap for a while when we hit a bit of crap steel. Sometimes it can be right down one edge of a plate. Makes the operators think the beam alignment has gone out.
Jonathan, the ribbon cable is around 2.5mts in length at the moment. This might get shortened a bit when I decide where I am going to mount the box.
Hi,
I know I'm a bit late coming back with this but..
Just curious, did you use a brake resistor on your high power drives?
Andrew
Brake resistor allows the VFD to stop the motor faster ... increases the deceleration.Quote:
Originally Posted by andrewbond
Sounds good at first, but really since the spindle stops in about a second without one, and my lathe will stop on the VFD in 2.5s without a brake resistor I really don't see the point. You're just stressing the motor more by putting a much bigger force on it during deceleration. Or if it's on a lathe the gears/keyways in between will wear faster.
The only exception to this is for an emergency stop where you want the spindle/motor to stop as fast as possible.
Andrew,
no brake resistor. I just let the spindle slow down as normal.
Ian
I meant the resistor terminal on the stepper driver?
Andrew
Andrew,
sorry I misunderstood you as well. No I didnt fit one to the driver either. I remember speaking to one of the manufacturers techies and he said that it wasnt needed.
Ian
I had decided that I was fedup with using the keyboard to jog the machine around and started to look at the idea of using joystick controls for the X, Y and Z axis. The USBCNC control board I am using does not have any inputs for joysticks so I looked at a USB keyboard interface and I found this one. Which fitted nicely inside a spare enclosure I had. I emailed the supplier and outlined the requirements I needed and he customised the interface for me. Including postage it was around £32.
Attachment 5233
The box lid drilled out and one of the joysticks wired.
Attachment 5232Attachment 5231
Both joysticks fitted to the lid.
Attachment 5234
The nearly completed controller apart from the labels. Need to change the size of them to fit the left side of the joystick without overhanging the side of the box.
Attachment 5230
There is no software to load, the USB port recognised the controller easily and it works perfectly alongside USBCNC V4.
Now I have joystick control for all axis of my machine. Much easier than the keyboard. Also this gives me the option of portability as I can have the control box in hand when positioning the machine.
Regards
Ian
that's a bit clever Ian
nice job
James
Now you just want it wireless!
Wireless? Now thats an idea. You do realise that I will probably spend most of tonight trying to figure out if I can make it happen!
Looks like it's either difficult or expensive:
http://www.ebay.co.uk/itm/Belkin-4-P...item3a6d135003
This should work with a bit of effort:
http://www.ebay.co.uk/itm/Arduino-Wi...item2563f68e18
Edit: It's rather slow though...
Edit 2: Slightly cheaper but still silly money:
http://www.ebay.co.uk/itm/Belkin-Hig...item19ccbb94d5
Now we know why people just use wireless Xbox 360 controllers.
I would also need to get a power supply for the box as well preferably a rechargeable one. For the moment I will stick with the cabled version but in the future whos knows?
Ian
As the old saying goes "If it works, then modify it to make it better".
I had a play with the usb keyboard interface I am using to get joystick control for my machine. The thing I was missing was feedrate control for jogging so decided to add some.
The initial jog speed is 10% of full speed after the machine is homed which is a bit slow. I have added buttons to map the keys for 50% and 100% speed override to give me much faster jogging speed. I also changed the orientation of the controls to make it easier to hold and use. ( No wireless though :tongue: )
Attachment 5268
You can view a short video of it in action here : http://www.youtube.com/watch?v=OSb7vJyVlIY
Regards
Ian
Looking good Ian, BTW i forgot about your pm ill reply to it later ;-)
The acceleration settings you have used look much too low to me. What have you set it to? Should be aiming for at least (roughly) 1m/s^2.
Jonathan,
the setup page on USBCNC for acceleration shows Acc.[AU/S^2]. In this box I have left it set to 50 which is the default setting. I cant remember what this setting means. I think I did ask Gary at Zapp about this a while ago and I have been looking through some old emails trying to find the answer but cant find it so I dont really know what Ive got it set to. I think I will have to email Gary again about it.
Ian
It sets how fast the speed of the motor can change, which is important since when the machine changes direction one or more axis must accelerate and decelerate, so if the acceleration value is too low the feedrate will reduce significantly every time it changes direction which includes just moving in arcs and circles. In addition to increasing the time taken to cut it causes the chipload to vary on the cutter which, depending on the size of the cutter, could damage or at least increase the rate of wear.Quote:
Originally Posted by Web Goblin
See 3.4.3.2:
http://www.planet-cnc.com/files/CNCUSBController.pdf
Assuming you're using millimetres, the value is probably in mm/s^2 in which case 50mm/s^2 is far too low. You want more like 500-1000mm/s^2, but not too high as it can cause the machine to shake excessively. Keep increasing it until the motor stalls, then back off a bit to be safe.
As 50mm/s^2 is such a small number you will notice a big difference in the time it takes to cut most things, but particularly parts with small moves, such as engraving.
Hii Ian,Quote:
Originally Posted by Web Goblin
I've just taken delivery of a USB-CNC 9 axis board....not sure if you know, but there's now a proper support forum (it's only opened recently)....
http://forum.planet-cnc.com/index.php
the software author (Andrej) is very responsive to posts on there.
Its USBCNC and not CNCUSB. They are different bits of software.
Fair enough, but this is very basic / universal concept so it shouldn't make a difference.Quote:
Originally Posted by Web Goblin
Jonathan,
You could be right but the manual doesnt specify this. I have emailed Gary at Zapp so he can remind me.
Ian
Jonathan,
I have recieved an email from Gary and he descirbes the App/unit as being made up of mm per step of the motor/ seconds squared.
So it looks like you are correct in what you were saying. I will increase the setting to 500 first of all and see how the machine performs and maybe get higher than this depending on how it is. I have noticed in the newer version of the manual that the setting page does have a value of 950 in the Acc. box so I will see what I can get my machine to run comfortably at.
regards
Ian
Jonathan,
I have altered the acceleration setting to 300 and this seems to be ok. I did try 500 but this wa a bit too abrupt for the machine, it was shuddering a bit at start and stop. I need to email Gary at Zapp to see if it is possible to alter the acceleration and deceleration distances in the software. If this can be changed then I could have a bigger acceleration value.
The new bed for my machine arrived yesterday but this needs a fair bit of work to get it finished to what I have planned. Its 15mm thick aluminium at 1260mm x 910mm. It needs to be cut to 1250mmx900mm then fitted, levelled and drilled and tapped for clamping.
Attachment 5347
Regards
Ian