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familyguy
27th Jul 2021, 05:41 PM
I've completed the first stage of my manual to CNC Arboga mill conversion, I decided to use a ball screw hung off the side, a 700N gas spring is mounted on the other side to balance/reduce the weight, IF - and that is a big if - this works OK I can lock the quill in place for CNCing and still have the use of the quill if I need to. The other option was utilise the existing rack and pinion, this would have relied somewhat on gravity to eliminate any backlash - a ballscrew seems to be a more positive system and any backlash would be from the ballscrew and nut plus any flex in mounting system/drive belt.


I initially mounted just the gas spring on it's own and found that it more than balanced the weight and had a slight positive affect on the system - once the stepper and ballscrew (which are not light) were fitted I estimate the overall weight of the Z axis system that the stepper has to lift is around 5-10 Kg plus any friction, the gas spring unfortunately does not reduce the mass so the stepper still has to contend inertia plus the weight + friction.


The ballscrew is 25mm x 5mm pitch the drive belt is 18mm wide 5mm pitch with a 2.5:1 ratio - the stepper is closed loop Nema34 12Nm 1.8deg per step, these are not a full closed loop system but a sort of hybrid system in that the stepper provides feedback to the stepper driver so the driver can try to regain lost steps should these occur, if the lost steps can not be made up the driver can alert/signal the motion controller - how the motion controller handles this depends on the motion control software and is a bit of an unknown for me at present. The 2.5:1 ratio multiplies the motor torque - it can easily be changed with different pulley sets and possibly removed altogether if I mount the motor directly above the ballscrew for direct drive.


The ballscrew nut mount is a section of 70mm square tube that was left over from a long ago carport build, the ballscrew top bearing and motor mounts are made up of 100mm wide Al plate, 15mm thick for the bearing mount and 10mm thick for the rest.


With everything bolted up tight and a DTI placed under the quill I could not detect any backlash when I rocked the drive pulley back and forth by hand, next step for me is to temporarily wire up the motion controller, bumble my way through the setup procedure and do some tests on backlash and possibly speed tests as well.




This all new to me, while I think I'm headed in the right direction with what I'm doing, I may well not be - I did vow at one time that I would never venture into 3D printing or the CNC world - I've had my 3D printer for over a year and now this.

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OxxAndBert
27th Jul 2021, 09:46 PM
Good progress!
I think you’ve said previously but I can’t recall the answer - what controller/software are you going to be using?

Steve

caskwarrior
27th Jul 2021, 10:34 PM
How will you deal with the column locks? I have a very similar modig drill and its not much of a mill but its a great drill.

Sent from my SM-G973F using Tapatalk

familyguy
28th Jul 2021, 12:14 AM
Controller is DDCS Expert stand alone(offline) 3/4/5 axis I think it is the same as a FOINC 350 - reading posts from various forums most use the Fanuc post processor, there is an active Facebook group with what looks like a lot of users but not a lot else so if I have issues to solve I'll be pretty much on my own - I did a lot of looking around and did not really find any 'turnkey' solutions for manual to CNC conversion unless you go the route of buying a fully built and working CNC mill - my budget does not extend that far.


The column locks - I have been using it for quite a while without locking the column, took a while to get the column gibs just right - a good cutter sharp cutter and easy does it, I have never driven the mill hard - locking the column helps if using a single point cutter like a boring head or a flycutter, I can't see myself using them in a CNC situation. As I said it is all new to me - using the column for the Z axis may turn out to be a bad idea, if so I can always do what many people have done and use the quill - a stepper on the fine downfeed, I've purchased a small stepper for the 4th axis I have planned and can always use it on the quill, another thing that I could possibly try is a solenoid on the column lock, the controller has 24 outputs for driving such things as coolant pumps, air lines etc it may be possible to operate a solenoid from one of the outputs.

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Michael G
28th Jul 2021, 09:17 AM
...using the column for the Z axis may turn out to be a bad idea, if so I can always do what many people have done and use the quill - a stepper on the fine downfeed...

As a general rule, keeping the quill as short as possible while milling reduces wear and tear on the mill. Driving the table up and down will give you a more rigid set up.


The column locks - I have been using it for quite a while without locking the column, took a while to get the column gibs just right - a good cutter sharp cutter and easy does it... another thing that I could possibly try is a solenoid on the column lock, the controller has 24 outputs for driving such things as coolant pumps, air lines etc it may be possible to operate a solenoid from one of the outputs.

That is something that is worth looking at, as once again it will increase rigidity & improve surface finish.

Michael

familyguy
28th Jul 2021, 05:19 PM
I cobbled together some components and in the first instance powered up just the motion controller to set up the Z axis parameters. The large square transformer is 245v to 215v - this powers the 2 small 24Vdc power supplies - 1 for the motion controller system power and the other for the IO power that provides voltage for control signals to the stepper drivers and anything else that may be connected to either the input or output ie coolant pump relay, limit/proximity switches etc. In theory I shouldn't need this type of drop down transformer - but the 24Vdc power supplies are 220Vac input and my mains voltage hovers around 240V to 247V so rather than take chances I'll be using this transformer in the final build.


The toroid transformer is one I had earmarked for a power amp project I intend to build in the future - it has 2x50V windings so for the test I'll be using 1 winding for 50VAC into the stepper controller - the stepper controller can take either AC up to 80V or DC up to 100V.
After double checking connections and voltages etc I power it up and there was panic for a few seconds when the screen did not come on instantly but once the loading system message appeared I was able to start breathing again, the screen is colourful, has a lot of pages/screens of information and I can see that for some time I'll be going around in circles wondering how to get back to a particular menu or screen, I eventually found my way to the axis setup screen but didn't get very far, I found I couldn't change any parameters unless I was signed in as a supervisor - time to go back and read the user manual.

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familyguy
29th Jul 2021, 11:40 AM
After sorting out the password, there are 3 levels of access (bottom level is 666666 - double devils number, is this an omen?) I still could not get any movement from the Z axis, - it dawned on me eventually that the stepper driver dip switches may not be set and sure enough they were set for maximum micro-step, with this reset for no micro-stepping I had up and down jogging. The motion controller user manual is not bad and does not read like a google translation from Chinese to English - but even so I could not find where to jog a set number of steps so I could do some preliminary checking of backlash so I turned to the MPG controller. Plugging this in gave me nothing, checking and changing some of the parameters for this device still gave nothing, not knowing if it had some sort of fault like loose wires or bad solder joints or if there were some other settings deeper in the motion controller that I hadn't found I decided to open up the MPG controller and have a look, while the build quality is ok I saw a few wires that had been extended, not great but what do you do when the wire has been cut off too short to reach the solder joint, I did find one bad joint, the wire had come away completely, after fixing this didn't change a thing, the motion controller has a screen that shows the status of all of IO ports - MPG port is one of these, I could see the rotary encoder was working but there was no other activity - something is not connecting with the IO power supply, then it hit me I could see I had not connected the 24Vdc supply at all, great work I thought. With power to the IO ports, the MPG (manual pulse generator) worked seemingly as it should, I was able to do a preliminary test for back lash - DTI under the chuck and zeroed, move Z axis up one full turn of the rotary encoder up and then back down one full turn, the DTI returned to zero, so far so good but I feel there must be more to it as far as checking for back lash, I'll need to do some more youtubing.

familyguy
2nd Nov 2021, 12:03 AM
I've been making slow progress with my CNC conversion - even though I vowed to do no more electronics repairs, I guess I'm just too soft and found my self with an amp, 3 speakers and 4 output transformers to wind, I did though manage to farm out the table and get it machined to allow clearance for the X axis ballscrew nut - the Z motor mounts were done and tested a while back - the X and Y motor mounts are finished and I am at the stage where I could reassemble everything and only have the electronics in the control cabinet to mount and wire up. But with the XY table on the bench now would be the time to add some lubrication grooves and external oil points to the dovetails and also the ballscrews, the mill had no lubrication grooves at all. I did a trial assembly of the Y axis and connected it up to my jury rigged controller setup, not surprisingly there is no backlash I uploaded 3 small videos to you tube, Z axis trial, Y axis trial and using the MPG controller to elongate a mounting hole on a Chinese XY table.


While the XY table has been out of action I purchased one of the el cheapo Chinese XY tables from the 'bay', it can be seen in the video sitting on the floor - I mounted it on the mill base so I still had a functional mill that I could use in making the X and Y motor mounts - also my ballscrews did not come with keyway slots which I need for the 'flexible' couplings between the motor and ballscrew, while they are not really flexible they do tolerate a small misalignment that might creep in.


The Chinese XY table is not great but adequate for what was asked of it, I found I had to adjust the gibs constantly for the first few hours of use and it seemed to get better the more I used it. It is obviously made as quickly and cheaply as possible and from viewing youtube videos the build quality of them is very variable, mine does not seem too bad - I did notice that not one edge had been broken so I ran over every corner with a file before the inevitable happened. If the MPG controller turns out to be PIA for manual milling then I may use the Chinese XY table bolted to the main mill table for used as a manual mill for quick jobs like cleaning up a saw cut.


The aviation style connectors I ordered finally arrived and I realised that I did not take a great deal of notice of the size, the 6 pin connectors are ok for the stepper feedback cables but not for the main wiring that powers the motors, pins are small and I was not keen to have 6-8 amps going through them - I located some ex military connectors in Lithuania, seller was very helpful, they arrived quickly and look to be up to the task.

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https://www.youtube.com/watch?v=QpD7WQyAAQs
https://www.youtube.com/watch?v=p1nUxvbOujo
https://www.youtube.com/watch?v=bDaxn1OnPUQ

familyguy
17th Nov 2021, 10:49 PM
I'm getting closer to finishing the XY ballscrew and stepper mounts, I decided to go with a simple gravity feed oil system for the slides and ballscrew - the slides and ball screws are fed via a small bore (4mm OD) copper pipe which leads back to an oil cup mounted on the rear ballscrew cover - one for each axis. I tested this with the XY table assembled on the workbench using ordinary 30/40 motor oil from my workshop oil can, takes about 3-4 hours for the oil cup (5ml when full) to empty, I notice that the motor oil does create some drag so when it is finally finished I'll investigate the use of something less viscous. I know it is not ideal to have the ball screw on the same feed as the slides but looking at other diy conversions on youtube I see many don't bother with oil feed to the ball screws and I figure that any lubrication is better then none, being for hobby use I can't see the ballscrews wearing out in a hurry, in addition if they wear out they are readily available - not like the original lead screws - acme thread, 0.2inch pitch, 0.875 inch diam, I'm expecting to add 2-3ml oil every few months.


The X axis ball screw is covered by the table but the Y axis ball screw is partially exposed so I made front and rear covers/shields for it, the covers are wide and deep enough to cover the sides as well, these were made from 2mm thick steel plate, my folder had no hope of bending 2mm steel plate so I cut out the individual bits and tried stick welding, the first cover warped badly and while I was able get it sort of straight it looked crap so had to be thrown out, for the next try I used the oxy and fusion welded it together - by the time I was nearing the end of the 2nd cover I was getting pretty good to the point where I didn't need to file/cleanup the welding and the best part is not even a hint of warp. The motor mounts are fabricated from heavy angle iron and 6mm plate, every thing slid together nicely with almost no issues, but - the X axis had a bad shudder in one direction only when the ballscrew was turned by hand, I eventually traced this down to the ball screw being a fraction too long and rubbing on the underside rear of the table, just touching it, I'll cut a few mm off the end.


The clearance machined for the Xaxis ballscrew mount broke through to the top of the table so I had to make up an cover, held in place with 4x3mm screws, once it is up and running I'll seal this with a bit of silicon - just in case I use flood coolant at any stage.


I still have a way to go - I've wound 2 transformers so I can use linear power supplies, a single transformer for the Z axis and a larger toroid with 2 secondary windings for X and Y axis, I was going to run straight AC to the stepper drivers but am now leaning towards a bridge rectifier and reservoir capacitors.
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familyguy
9th Dec 2021, 11:39 PM
Made some more progress on the CNC conversion, I don't really have that much more to do to make it functional but it still seems to be taking forever - after looking at a number of options for a control box I decided to incorporate it into a small cabinet with benchtop and drawer, made with 25mm squ tube steel frame and sides covered with colour bond steel sheet, a door on the side and a removable top give reasonable access to the inside. The motion controller sits in a sloping front metal enclosure that is slightly raised on a 60mmx25mm steel tube, all the cables to and from the controller run through the tube. The cabinet holds the fuses, power supplies, VFD drive and the stepper drivers. All drive and control connections from the mill to the control box are with aviation style connectors, 3Ph power from the VFD to the mill is via a standard 3ph plug and socket. I used a scrap bit of Al the for the front panel of the motion controller cabinet, once it's working I'll make a new one and do the engraving on the mill (I hope).
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familyguy
17th Dec 2021, 01:25 AM
The X and Y axes are all wired tested and working in jog mode - parameters set for the micro stepping setup I'm starting off with - not sure about micro stepping I understand that it increases precision at the expense of speed - I have started with 800 steps/rev against the motor default of 200 steps/rev this should give me around 2 tenths of a thou resolution. The motors are connected to the control cabinet via aviation style connectors a large 4pin for the motor drive and a smaller 6 pin for the feedback encoder, I didn't really pay too much attention to the size of the small connectors when I ordered them and found they are quite small, even though I've been soldering for over 1/2 a century I did find them quite fiddly and silently cursed myself a few times while soldering.
I thought I'd better come to grips with something simple to try as a first project - engraving a new front panel for the motion controller box - I could see that the mill would be operational soon and I wouldn't know how to use it - I bumbled my way through Fusion360 one evening to come up with a small engraving NC test file using a Fanuc post processor. From experience I know that it is asking for trouble operating machinery if everything is not properly connected and secured but I couldn't resist trying it out in 2D - felt pen in place of a cutter - the Z axis wiring is not complete/working so the complete tool path is drawn out - link to the video - not very exciting stuff but gratifying for me to see.


https://youtu.be/gXUPXkv5Ql0

pippin88
17th Dec 2021, 07:31 AM
Microstepping improves smoothness (reduces vibration) more than anything. Cannot be relied upon for accuracy.

https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/

familyguy
22nd Dec 2021, 11:37 PM
Before all work stopped for Xmas and the endless meals etc. I managed to make some progress on the conversion and all 3 axis now working - even though I was keen to do some trial cuts, I was a bit hesitant - a manual machine gives you some feed back through the lead screw handles that you don't get with cnc, but at the end of the day the worst I can do I thougfh is break a cutter. I ran into an issue and while I can work around it it would be nice to sort it out, at this stage I'm not sure if it is a Fusion360 thing that can be fixed with a check box or if it is an issue with the motion controller setup. In Fusion I set the lower left corner of the work piece as the ref point or origin when setting the tool path and generating the nc file - on the mill however the part will be mirrored so I have to indicate the top right, which effectively makes the part upside down if I stand at the back of the mill then it looks right - I have some research to do here.


For the test cut I machined a 3mmx3mm groove around the edge of a piece Al from a failed project, the need for the workaround aside it was pleasing to see it worked - could I have done this manually - clearly for something as simple as this the answer is yes and it would have been quicker. A link to a video - not very exciting plus a bit shaky I was trying to keep the Estop button in sight, just in case.


https://youtu.be/IgIwLlxmeOA


I still have a fair amount of work to do - tidy up the stepper motor cables, currently just hanging on the ground, organise a coolant/air blast system, make a top and drawer for the control cabinet , hang the control cabinet door and make and engrave a front panel for the motion control enclosure.

BaronJ
23rd Dec 2021, 07:44 AM
Hi Familyguy,

Check the rotation direction of the X - Y steppers ! If one is running in the wrong direction that is the effect you get ! A bit like swapping phases on a three phase motor.

familyguy
23rd Dec 2021, 10:02 AM
Hi Familyguy,

Check the rotation direction of the X - Y steppers ! If one is running in the wrong direction that is the effect you get ! A bit like swapping phases on a three phase motor.

That seems logical, the direction of the steppers is easily changed in the stepper driver and in the motion controller parameters - however the motion controller has a set of jog buttons, changing the direction of the motors would reverse the jog button operation, pressing left jog button would move the table to the right and I feel that's not intuitive and asking for trouble to operate this way. At present moving the table to the right is shown as a positive direction (counting up) on the DRO, and this at first glance this seems right but as the Z axis is stationary the Z axis movement is in a negative direction (to the left) relative to the table - the DRO should be counting down. I'm hoping that one of the 250 setup parameters will fix the issue, some of the parameter descriptions in the manual are a bit confusing and I'll need to set a few hours aside to play with the settings, probably after Xmas - the next 5 days aren't mine but have been given to endless road trips, meals and cooking.

OxxAndBert
23rd Dec 2021, 03:22 PM
FWIW one of the youtube creators recently covered a similar thing. I think in his case it may have been a CNC plasma, but his comment was along the lines of "although I originally thought my brain could cope - it couldn't, and having the orientation on the display being backwards to the physical travel has caused me a few crashes".
So definitely stick with having your jog directions intuitive!

In his case it was a simple stepper direction change - but sounds like for you its a case of finding the layer/setting that doesn't match the rest of the system.

Although I can never remember which is which, probably the best thing would be to set everything so it conforms to the standard +ve and -ve directions for the axes. If for no other reason than it being "standard", so should mean that if you ever need to collaborate with an industry based CNC person or have someone looking over your shoulder - it won't fry their brain with the axes being backwards. Likewise if you're looking at someone else's gcode.

Steve

pippin88
23rd Dec 2021, 05:45 PM
There are well established conventions for axis direction etc.

You need to think of the TOOL moving, not the table.

As you stand in front of the machine:
Tool moving from left to right is X+
Tool moving from close to you, to far away is Y+
Tool moving up towards the sky is Z+ (moving down towards ground is Z-)

This is to have coherent set of directions from start (design) to finished part.

Sure you can reverse things. On a square block that's not too hard.
But what about a workpiece with existing features / funny shape? Reversing is inviting screw-ups.

Strongly recommend you set it up in the usual convention and train your brain.

Look at the tool in relation to the stock. Don't focus on the table.

familyguy
24th Dec 2021, 10:17 AM
There are well established conventions for axis direction etc.

You need to think of the TOOL moving, not the table.

As you stand in front of the machine:
Tool moving from left to right is X+
Tool moving from close to you, to far away is Y+
Tool moving up towards the sky is Z+ (moving down towards ground is Z-)



The way the dro and internal co-ordinates operate is fixed and looks like it can't be changed - right jog is positive - left jog is negative so I guess the controller follows established convention, I'm new to cnc and maybe this is how all motion controllers are setup.This is fine if the motion controller has been setup for a timber cnc router with the Z axis on an overhead gantry - a cnc machine with a fixed Z axis and a moving XY table is a little bit different in that moving the table towards the right brings the Z axis closer to the left side of the table so the dro (and internal co-ordinate system) should be counting backwards towards zero, I've done a little sketch to illustrate the difference - the X and Y axis have effectively been reversed.


This did create an issue for the person new to cnc (ME) - with my engraving test work piece clamped to the table I located my datum point at the lower left corner - this is the point I picked when working out the tool path in Fusion360 - I zeroed all 3 axis to that point - press start and wait - the engraving did take place but not where I expected - it was upside down and moved to the right. My workaround was to rotate the workpiece 180 deg then clamp it down - the same datum point is used as the zero reference - in this instance it would now be at the top right, this does work I tried it, I can't see that an odd shaped workpiece would cause problems. There is another way though, I found Fusion 360 has an option to flip the X and Y axis at the time you are working out a tool path so no need to flip the part on the mill table and I guess this is what I'll be doing - being totally new to cnc I don't know but maybe this is just standard procedure.

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pippin88
24th Dec 2021, 06:34 PM
I don't quite follow you about what happened with the engraving.

You need to think about the tool moving in relation to the workpiece.

Forget about the table moving.

Look at the tool and the stock.

X+ moves the tool rightwards in relation to the stock
(This means table moves left on a mill).

You may have axes reversed.

X+ jog should move the tool rightwards in relation to the stock (table moves left)

Can you show a video?

familyguy
25th Dec 2021, 11:00 AM
I don't quite follow you about what happened with the engraving.

You need to think about the tool moving in relation to the workpiece.

Forget about the table moving.

Look at the tool and the stock.

X+ moves the tool rightwards in relation to the stock
(This means table moves left on a mill).

You may have axes reversed.

X+ jog should move the tool rightwards in relation to the stock (table moves left)

Can you show a video?

Yes you are correct - if I forget about the table moving and just look at the tool and the stock then X+ should move the tool closer to the stock and X- moves the tool back away from the stock, there are parameters in the motion controller for this, - I'll get a video or two uploaded once the Xmas family duties are all done with in a few days.

familyguy
8th Jan 2022, 04:53 PM
Relatives have departed and I now have some time to my self - I drew up a simple engraving test in Fusion and made a video - link is here

https://1drv.ms/v/s!AhR6y7vV52cIjBs5A-lH2t1F8jsV


In Fusion I set the bottom left corner as the 0,0 point and made a mark on the paper and set this as the 0,0 point of the work co-ordinate system, I expected (possibly incorrectly) the 'engraving' to take place in what would be the first quadrant of the cartesian co-ordinate system ie the right and above the 0,0 point - as the video shows it was down and to the right.


Just prior to making this post I downloaded a pdf copy of 'CNC Machining for Engineers and Makers' by NexGenCam it looks informative - now that I have a bit of time to myself I'll do some reading.

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pippin88
8th Jan 2022, 08:04 PM
You have both X and Y inverted.
A common mistake when setting up a moving table machine.
Depending on software may be an easy fix in software.

Or you can do it by changing the wiring. Swap the polarity of one pair on each stepper (assuming 4 wire motor).

familyguy
9th Jan 2022, 02:14 PM
Yes my axis were reversed - easy enough to change either in the motion controller parameters or at the stepper driver dip switches, I made the change and did another test run with the 0,0 point in Fusion360 set to the bottom left corner and used the same corner for the test run (felt tip pen again) - this time the engraving - letter G - it was positioned where I expected, the jog buttons however now operate the opposite way.


I have for now stuck some masking tape labels over the jog buttons, I'm a bit concerned that I'll jog the table in the wrong direction and wipe out a cutter or something even more serious. I'm not sure if this is the right thing to do as it doesn't reinforce the concept that I should be thinking in terms of the cutter moving rather than the table moving.


This is my first foray into CNC - I guess the feeling will eventually go away but it is a bit un-nerving to watch the machine take off on it's own, with me thinking have I done it right ? - is the cutter going to slice through my vice ?

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pippin88
9th Jan 2022, 05:27 PM
Can you make a video of the jogging including which button you are pressing etc

familyguy
10th Jan 2022, 12:28 PM
Can you make a video of the jogging including which button you are pressing etc


Link to jog buttons video


https://1drv.ms/v/s!AhR6y7vV52cIjCH1kbiR6IJ1ZhCd

familyguy
13th Jan 2022, 12:25 AM
A small update I drew up a 12mm sq x 5mm high block to be machined on the end of a bit a scrap Al I've been using for testing, the machining went well and end result looked ok but not great, but it came out a bit undersized 11.935mm x 11.933mm and a few hundreths of a mm tapered, I watched a few youtube videos on backlash and after some checking ruled that out, I checked the cutter for runout (ER collet chuck) and found just over 0.07mm, way more than I expected, no amount of cleaning, checking for burrs, remounting etc made any difference, I pulled the chuck and checked with a bench magnifier I could see a wear mark on the nut at the point marked W on the sketch - this is the eccentric bit that pulls the collet from the chuck, and the point at W is not supposed to touch the collet at all - being eccentric it was probably pushing the collet one side only - a minute or two on the lathe to skim a few thou off and the cutter runout came down to just under 0.015mm - not perfect but a huge improvement.

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BaronJ
14th Jan 2022, 08:41 PM
A small update I drew up a 12mm sq x 5mm high block to be machined on the end of a bit a scrap Al I've been using for testing, the machining went well and end result looked ok but not great, but it came out a bit undersized 11.935mm x 11.933mm and a few hundreths of a mm tapered, I watched a few youtube videos on backlash and after some checking ruled that out, I checked the cutter for runout (ER collet chuck) and found just over 0.07mm, way more than I expected, no amount of cleaning, checking for burrs, remounting etc made any difference, I pulled the chuck and checked with a bench magnifier I could see a wear mark on the nut at the point marked W on the sketch - this is the eccentric bit that pulls the collet from the chuck, and the point at W is not supposed to touch the collet at all - being eccentric it was probably pushing the collet one side only - a minute or two on the lathe to skim a few thou off and the cutter runout came down to just under 0.015mm - not perfect but a huge improvement.

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Hi Familyguy,

I have a couple of ER collets that seem a little tight in the nut, I'd assumed that the groove in the collet was slightly narrow.

Your picture explains a lot, thanks. :)

pippin88
15th Jan 2022, 12:09 PM
Link to jog buttons video


https://1drv.ms/v/s!AhR6y7vV52cIjCH1kbiR6IJ1ZhCdJogging is as expected.

X+ moves tool right.
Y+ moves too away.

You just gotta train your brain. Look at the tool. Don't look at the table.

nigelpearson
15th Jan 2022, 07:53 PM
Install 2 MPGs?

One above the spindle, which jogs the cutter relative to the job.

One below the spindle, which moves the table.

familyguy
17th Jan 2022, 08:53 PM
I now realise that thinking in terms of the tool moving is something I should get used to - I guess that I should be thankful for small mercies, actually getting the mill to machine or engrave has been quite painless, getting it to do so in the right place was a bit of a head scratch, I was hoping to find some sort of tutorial on youtube that explains the process from start to finish on setting up the axis, the home position etc. but found nothing that would really assist me. The publication I mentioned in post #21, I found for me was actually very good as it assumes no prior knowledge, explains the process and gives reasons why things are done a certain way, it has the look of a text book used for a tafe or trade course.


Getting used to the tool moving rather than the table moving reminds me of my car - the drivers seat is the memory type that is power operated with servo motors, to make it easier to get out of the car it retracts to the rear when the door is opened, even though I know this, I still at times get the feeling that the car is rolling back as I open the door when it is actually only the seat moving.


Install 2 MPGs?

One above the spindle, which jogs the cutter relative to the job.

One below the spindle, which moves the table.

I'm not sure at this stage how to rig up 2 MPG's - the jog buttons on the motion controller are not really like a MPG - they can be

(1) programmed (on the control panel ) to move a specific distance - either 1 of 3 presets or a custom distance entered by the operator, or

(2) operate in continous mode in one of 2 speeds - low or fast. The MPG controller has pulses generated by the handwheel with a choice of 3 user selectable speeds, and I don't think it was intended to replace jog buttons - I find it useful for touching off on the stock to set the 0,0 datum point, the finest setting moves around .001mm per pulse (I div on the handwheel).

familyguy
18th Aug 2022, 12:37 AM
Making a front panel for my CNC controller has been high on the list of things to do for some months now with other things getting in the way, but finally found the time to get the job done, designed in Fusion360 it was too big in the Y direction to do the lot with one set up. The edges of my spoil board are pretty much square to each other so aligning the panel on the spoil board for each operation for an easy thing.


With two setups/operations I needed two files so a second copy of the Fusion360 file was saved with a different file name, working with one file I rotated the panel 90deg anticlockwise and defined the 2 toolpaths for the engraving and then the for the bored switch holes, the same procedure was used for the bottom engraving etc with the other Fusion360 file, the engraving was done with a 3/16 centre drill 0.5mm deep in one pass, no detectable burr, a squirt of CRC as cutting fluid. The square cutout for the actual controller was also done in a similar with 2 operations as it was slightly over the max travel of my Y axis.


Rewired the spindle control so I can either have auto operation where the spindle speed/stop/start are done by the controller or manual human control, I also fitted an alternate set of jog buttons, wired to the controller external control inputs, the probe input socket is a small aviation style connector mounted on the side next to the MPG cable entry point, the probe can be either a tool height probe or a 3D edge finder type.