First steps with a Shapeoko router table

John, this is quite a good video that shows a couple of cutting options and talks about chip loads etc. and a good summary at the end. may be worth doing a few test slots like he shows in what is left of that workpiece before having another go at the conrod.

Michael, 25K rpm 2500mm/min feed of a single flute cutter and no burrs, does have a good grip of the workpiece though!

Edited By JasonB on 05/05/2021 20:25:09

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I’ve only skimmed through it, but ... That’s very impressive !

I note the heavy-duty fixturing, and the conspicuous absence of MDF

Sorry, John but I think you will need to be taking very light cuts, whatever the spindle speed.

MichaelG.

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Just found this ... in time for an edit:

https://www.ame.com/workholding-wisdom-posts/2021/03/10/the-role-of-stiffness-in-workholding/

Edited By Michael Gilligan on 05/05/2021 21:16:27

Me again, folks!

Having taken heed of Jason's wise words, I've relieved the shaper of its vice and mounted it on the router table. Fortunately only minor surgery to the bolt slots was required to align with the mounting holes in the wasteboard:

I also managed to mount a DTI directly in the router spindle in order to check the Y-axis tramming. The photo of the start, below, is taken from the video, so not very clear, I'm afraid.

Every journey has a start and an end and this is the end of that journey:

The DTI flattered to deceive as it remained solidly on the zero mark except for the last centimetre where it suddenly veered of by a miniscule* amount.

I'll publish a video later (probably tomorrow, now) and I think I'll gather them all together in a playlist as they seem, like Topsy, to just grow and grow in number.

John

*miniscule = a very small amount which I'm happy to live with.

I've taken a couple of days out to watch all the suggested videos and absorb as much of the advice as my poor old brain will take. Having reviewed the video that I took of the 2D pocket that I was trying out as a test, not only did the spindle veer off to the left of the stock, but impacted the cutter with such ferocity that it loosened it in the collet chuck. Upon closer inspection, it had also wiped both corners of the brand new carbide cutter. Out with the old and in with a new one. Back to the computer in the house and re-did the gcode with spindle speed 16,000 rpm, feed rate 1220mm/m and doc of 0.4mm. The simulated run in Fusion went well, so, with some trepidation, I ventured back out to the workshop and fired it up again. Set the camera rolling and pressed the 'go' button. Rapid movement to roughly the start position and wham! Down goes the spindle directly into the stock to a depth of 10mm and out the other side. Mad panic rush for the mains switch and peace is restored. I had to loosen the vice jaws to unlock the stock and spindle from their intimate grasp and inspect the cutter. Fortunately no damage had been sustained but aluminium had filled the flutes and welded itself to the cutter. Retired back inside to lick my wounds and have a cup of tea and a biscuit.

I have no idea what I'm doing wrong and, to be truthful, I'm getting more than a bit ticked off with it! I can only think that I'm setting some parameter or two (or more) wrong in the CAM section, somehow. But that doesn't explain why it works OK in simulation but goes seriously awry on the machine.

I think I'll have a go at wood next time, otherwise I'm going to run out of aluminium, none of which I would describe as scrap, or carbide cutters, or both.

My wife wants a new house number plaque, so maybe that might be a better proposition. I'm trying to run before I can even crawl, I think.

John

(Tail firmly between legs!)

Edited By John Hinkley on 09/05/2021 14:13:48

Possibly the height you are setting the tool at relative to your datum point.

When doing the CAM setup you can position the 3 way arrow at various points on the stock. I usually use the top as it is then easy to use a block of known thickness ontop of the work to set the tool height. I use a 20mm block and enter my tool height Z as = 20 that way the machine knows my tool is 20mm above the top which is my zero.

If you have that 3 way arrow at the bottom of the stock you need to set your height from there.

Jason,

I believe that you may have hit the nail on the head. I have been setting the X-Y-Z position in Fusion to the south-west corner on the top of the stock and this results, as I say, in the simulation running OK. The clearance height is set to 10mm.

When I go to the Shapeoko, I have been setting the centre of the cutter to the south-west corner of the vice-mounted stock and then setting ALL the axes to zero. If I understand you correctly, I should be zeroing the X and Y axes to that position, but raising the Z axis by 10mm (the Clearance height) and then zeroing the Z axis? Is that correct?

I'll give it a go tomorrow to see what happens.

John

No Stock top is Zero in that case, a clearance height of 10mm means the end of the tool will be 10mm above zero so clear the work by 10mm as it moves about from one position to another. If you are edge finding X & Y that is fine but what are you doing for Z? If touching off the top surface with a fag paper or similar then enter Zero. If you are using a block to gauge height which is safer than jogging the tool down too far then enter the height of your block as the Z value

Try a few air cuts with the height set well above the vice/stock and check all is well first until you track down the problem.

Damn! I am using the fag paper method of finding the zero position and setting Z axis to zero there. I'll abandon my last suggestion, therefore. I will set it as you say, then remove the ER11 collet chuck and cutter and try your air cut method. I should have plenty of airspace to play with that way.

Thanks for your patience,

John

I'd suggest first run with piece of balsa wood shaped like a cutter, cruicially same length protruding, and no stock or vice even in case the head whacks that. Then after two runs to double check move to cheap cutter and machinists wax or expanded polystyrene material.

Duck, everybody! Watch out for all my toys coming out of the pram ........

I tried the Shapeoko version of air-guitar and it seemed to work OK. The spindle - sans cutter and not running - moved from its zero position, appeared to do a helical cut downwards and proceeded to perform the pocket cutting manoeuvres. Great, I thought, I'll try it now with a cutter. I did, having set up the Z-axis to zero on the top of the workpiece. Switch on, run , set spindle motor running and press "go". Zoom, off goes the head and wang! straight down 10mm into the workpiece, then starts to try the helical cut. By this time my hand had reached the mains switch and I aborted the run. Another failure, more aluminium welded to the cutter and another hole in an otherwise useful bit of aluminium.

Somewhere along the line, I'm getting 10mm of unwanted downward motion and I can't for the life of me work out where its coming from. I strongly suspect I'm setting the tool heights wrongly in CAM section, but how, I know not. Don't bother looking for the video, I can't bring myself to string all these failures together.

I'm going to take a few days off to gather my thoughts and do a bit of gardening.

John

Well, I took a few days off to let my hair grow back and watch a few more videos. I revisited Fusion 360 and generated some new Gcode to attempt to produce a 2mm deep pocket in some MDF laminate flooring off-cuts. What happened is documented in this brief video:

Gives me a bit of renewed enthusiasm for further experimentation.

John

That's looking better, good idea to just use something a bit more forgiving while you get the hang of getting your heights and positions right, when you can do that consistently then try some similar shapes in aluminium

Hi ,
You could try this for test cuts ,re-melt into blocks or sheets for test cuts,
if the machine is clean catch the wax swarf and re-melt again to reuse.
No blunted or broken cutters.

MOULD CASTING WAX 2KG FOR LOST WAX INVESTMENT CASTING

from

https://www.artisanfoundry.co.uk

Similar to this prototyping wax.

John

One small step for Man ... one giant leap

MichaelG.

Jason - yes, I’m going to try some more shapes and different cutting styles in the next few days.

John - that looks interesting, but I have a large supply of those mdf floor laminates to munch my way through, first.

Mike - I’ve heard an expression similar to that before, I think!

John

Just a quick update on the import duty/VAT situation. I've left it until now so as not to tempt fate ...........

I have received NO invoice from Fedex at the time of writing. I have contacted them twice asking for information on this specific delivery and all I got was a standard reply inviting me to open a Fedex account, which I have declined - I have no use for one. So, either I've "got away with it" or I can expect the bailiffs to be knocking on the door anytime soon, demanding wads of cash.

John

Risking boring you all with my failure to get to grips with Fusion and the router, I've just posted this video on YouTube. It represents an improvement, of sorts, in my understanding and implementation of the CAM function in Fusion 360. The first three processes went OK, but when I stopped to change the cutter and then reset the Z-axis zero accordingly, it went downhill, extremely rapidly. At about 1220 mm/sec actually. What performed perfectly within Fusion in simulation mode, suddenly drove itself into the work by an extra 5mm or so. I've checked the code for depth errors and everything looks OK. I think I'll try to get some reducing sleeves to fit the 4mm and 6mm end mill cutters into the DeWalt 8mm collet, to reduce the loss of headroom when using the ER11 chuck.

Any significance in the timing of the above posting, do you think?

John

Pure coincidence, by the way. I didn't do it on purpose .

Well at least the MDF is a bit more forgiving, I can't see anything obvious as to why it cut too deep. I assume you are touching off on the top of the stock each time and entering the Z height as Zero each time.

Luckily I did not have the video running yesterday on the conrod that I mucked up along with snapping the cutter, always seems to be the last stage that things go wrong, I can see what it did in Fusion and mush have been playing around with it between checking the simulation was OK and doing the post processing

That’s hard luck, Jason, but reassuring for me to know that more experienced people can have these issues too. And yes, I did touch off on the stock and re-zeroed the Z-axis after changing to the ball ended cutter. I have a couple of tweaks to try before attacking another piece of mdf.

John