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Topics - mc

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1
Show"N"Tell ( Your Machines) / A Wee Prober
« on: July 30, 2014, 12:53:37 PM »
I've been needing something to accurately probe some parts for a while, so after much deliberation, a plan has been sketched and bits purchased.

The first major part turned up today -

Key Component 1 by mc_mtb, on Flickr

With the other major part finally being released from customs this morning, so I'll hopefully have that by the end of the week.

There's also the mandatory box of various bits and bobs, but I'm sure you don't want to see a big box covered with RS logos ;)

2
General Mach Discussion / Lathe threading wizard issue
« on: March 25, 2014, 03:01:32 PM »
When I try using the Lathe Threading Wizard on the new lathe, it won't let me change the X Start value.
It's currently stuck on 3. If I try changing it, it'll very briefly stay after hitting enter, but in the blink of an eye it changes back to 3.

It was stuck at 1 when I tried it a couple days ago, but yesterday it changed to 3.
I can change the relative values manually in the generated code, and it works how it should, so it seems to be an issue with the wizard.

Anybody got any idea what could be the problem?
I'm running .057 incase it makes any difference.

3
General Mach Discussion / ATC and selecting tool issue
« on: February 25, 2014, 06:29:58 PM »
I'm finally getting around to finishing of my cyclone, but during testing various things, I've discovered an issue with selecting tools.

If I issue a full tool change command i.e.T0101, things work fine, however if I command an abreviated version i.e. T01, then it requests tool 0 which is invalid (it has also highlighted an issue with my PLC logic, but that's another issue).
Is this how Mach turn usually works?
Or have I missed something?

Here's my toolchange macro-
Code: [Select]
oldtool = GetUserDRO(1202) 'Get the current tool position (we could use GetCurrentTool, but UserDRO1202 is updated directly from KFLOP via the macropump)
newtool = GetSelectedTool() 'Get the new tool position
if oldtool = newtool Then 'if we've already got the requested tool loaded
End 'then we can quit this macro without doing anything
End If
ActivateSignal(Output10) 'this activates the tool change allowed signal from the KFlop to PLC (KFlop bit 144 - Port2Pin16)
SetOEMDRO(1006,newtool) 'transfer the new tool position to the OEMDRO (transfers to KFlop persist, where it gets transferred via MODbus to the PLC)
NotifyPlugins(19006)
While Isactive(Input1) 'wait for tool changer OK signal to turn of (this is so we know the new tool position has been transfered)
Wend
While not Isactive(Input1) 'then wait for tool change ok signal to turn back on - KFlop bit 141/port2pin13
Wend
DeactivateSignal(Output10) 'turn of tool change allowed signal
SetCurrentTool(newtool)
End
I'm using a KFlop, which communicates with a PLC via modbus to control the toolchanger.
I've checked and the KFlop is being sent a request for position 0, so I'm sure this is something Mach is doing.


One other quick question while I'm here.
If I add code into the Macro to check for a valid position, what code is needed to halt the current program if an invalid position is requested?
i.e.
If newtool < 1 or newtool > 6   Then
   What goes here to bring everything to a halt?
End If

4
General Mach Discussion / Tool changer question
« on: November 18, 2013, 12:35:57 PM »
This is for a lathe, but the same issues apply to a mill aswell.

While running G-code, the tool change scripts handle everything, but what happens when you're not running a G-Code file?

For example how do you cycle through tools while setting up/checking/changing them?
Do you have a dro setup for commanding a certain tool number, just rely on typing into the MDI, or....?

The reason I'm asking, is this is the first time I've had to deal with an ATC, and I'm not sure what the usual/best way is of dealing with it manually, so I'm not sure on how best to set up a custom screen to handle it.

5
General Mach Discussion / Mach Turn - a couple questions
« on: November 04, 2013, 06:25:26 PM »
I see various mentions of 66 having issues regarding turning, so what's the newest recommended version for turn?
Or more precisely, what are the known bugs in the later versions?
I think my little lathe is still running 22, and I adopted the "if it's not broke, don't fix it" attitude so have never bothered upgrading it to any of the later versions, however for the new lathe I figured I'd better update a bit.


How do people handle tool offsets with turrets?
I know you can have tool x loaded in tool position y, but when the tools are swapped, they're never likely to ever clamp back in the exact same position, so is there anypoint in having offsets for every tool when they'll need to be reset when the tool is refitted?

6
General Mach Discussion / How to handle servo faults
« on: September 22, 2013, 04:28:52 PM »
Originally I had planned to link the servo driver fault output into the e-stop circuit, so that if a driver faults out for any reason, the main power to all the drivers/spindle gets cut.
However, the issue with that is the drivers logic which is on a permanent 24V supply, would flag up a fault due to low voltage, meaning that to get them out of fault and power up the e-stop circuit, the drivers fault outputs would have to be bypassed, and a driver reset signal sent to all the drivers. Which although doable, would involve a few relays and a couple outputs.

To simplify things, I was thinking instead, just rely on the driver ready signal fed into the controller (I'm using a KFlop, so the controller itself can handle this and then report to Mach there's an issue) and halting motion if a drive enable signal fails.
I know it's not ideal, but then there are still limit switches to trigger an e-stop things if anything major goes wrong.

Does this sound feasible?

Also, I'd be interested to hear how others have servos wired up to deal with faults.

7
Show"N"Tell ( Your Machines) / Denford Cyclone retrofit
« on: September 21, 2013, 07:36:46 PM »
Whilst lounging about on holiday last month, this popped up on the radar

New Toy by mc_mtb, on Flickr

Once back from holiday, I had been planning to order all the bits to get my Matchmaker mill up and running, then look at getting something bigger to replace my little Conect lathe, however this Cyclone happened to pop-up just before I ordered anything.
My main reason for purchasing it, is it's a 35mm through hole version, which ties in nicely with my future plans. It also comes with a 6 position toolchanger.

Initially I was going to go a for a quick retrofit using a PLCM-E3 controller coupled with the PLCM-B1 BOB as the BOB is 24V tolerant, so connecting everything would of been reasonably straight forward, with the only other items needed being a couple stepper drivers, a bridge rectifier, and a big capacitor to give me a power supply for the steppers, however the PLCM stuff was out of stock in the UK with a lead time of two weeks. Also some reading up that the PLCM doesn't support threading, and all english pages disappearing from their website put me of using it.
Instead I've opted for a bit more involved retrofit, using the Dynomotion KFlop+Kanalog I had already bought for the mill, and fitting servos.

Here's the control cabinet prior to delivery -

Electrics as Delivered by mc_mtb, on Flickr
The original setup used an Optimised Controls rack fitted with a Eurostep controller, and rack mount Parker SD15 drives.
I spent some time today removing the old rack along with the wiring I know I won't need, and getting the Kanalog and servo drives mounted in place. I also managed to get an extra single phase contactor for the servo drives in place and connected into the E-Stop controlled supply.
As of this evening, this is how the control cabinet sits-

Out with the old, in with the new by mc_mtb, on Flickr

I'll hopefully start getting things wired up tomorrow.

8
General Mach Discussion / ITX Motherboard suggestions?
« on: July 15, 2013, 04:11:40 PM »
Has anybody got any recommendations for a cheaper and current ITX motherboard?

The popular ASRock PV540A is no longer commonly available (in fact, I'm struggling to find many ASRock boards commonly available just now), and I'm looking for a cost effective replacement.
I don't need a parallel port, so that does give me more options, but I'm just wondering if anybody has any recommendations.

9
General Mach Discussion / Tapping on a non-reversible lathe
« on: February 11, 2013, 03:46:12 PM »
If I was to build a simple tap holder, that is capable of disengaging and letting the tap spin after a set distance, what G-code would you use?

I'm trying to eliminate having to move the parts to my manual lathe, just to run a tap up the centre. If I could do it on my (little) CNC with a non-reversible DC spindle, running the tap back out by hand will still be quicker than swapping lathes.
I'm thinking a tap holder that's mounted onto a round shaft, and when retracted is held stationary by a couple drive dogs/pins. Just before the required thread depth is reached, the Z-axis stops moving, and the tap holder keeps going until the the drive dogs disengage. I'd have the tap holder always slightly floating, to allow for Machs lack of rigid tapping or speed/syncronisation variations.

This isn't going to be a long term solution, as I'm already planning a bigger and better lathe, so I'm trying to spend as little money as possible.

10
General Mach Discussion / Lathe tool change problem
« on: January 14, 2013, 05:32:10 PM »
This problem has existed since I started using my lathe, but I managed to tweak the g-code to get around it, but having just hit the problem again tonight, I want to figure what is actually causing the problem.

When changing between tools in the g-code, if there is a large distance on the X-axis needing moved, lots of steps get lost/the stepper stalls.
Tool changes are fine as long as the x-axis distance needing moved after the tool change is minimal (or is combined with a long Z move).

For example, if the new tool offset is 80mm different, and needs a physical movement of say 2mm to get to the next commanded position things are fine, or if it needs to move 100mm in the Z and 80mm in the X, things are fine.
However, if the physical movement needed is say 50mm in the X alone (or combined with a few mm in the Z), the x-axis will stall.

It's as though Mach ignores the max speed of the X-axis for that first move after a tool change.
If the first move is combined with a long Z move, because the two are interpolated to move diagonally, things go fine.

I'm not sure if it's related to some setting (G0 moves never cause any problems, and I've even tried reducing the X-axis max speed when I first had the problem), a bug with the SmoothStepper, or something wrong with Mach.

Anybody got any suggestions?

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