El Beast - Initial design phase, comments and critique welcomed!

Beautiful. This build oozes quality. Looking forward to seeing it run.

Wal.

Very kind, but if you want to see quality go visit routercnc's thread ;)


So I was going to show you some lovely Z-axis end plates, but I goofed them up (I know, shock horror right?). I must have put in the incorrect stock dimensions as it just missed the back edges by a fraction... something also went a bit wrong when doing some interpolated drilling and my X axis shifted by 1mm. Something I've never seen happen before on this machine.... Can't have been the motors skipping steps as they are closed loop and would have faulted so something perhaps happened on the PC end. As it happened it wasn't a big deal, just resulted in some messy and over sized internal screw holes but combined with the other mess up and I'm just going to bin them and start over... I can take the opportunity of having seen them to do a few little design tweaks at least.

So close but no cigar:

Roughing - 8mm DoC, 1mm WoC, 1500mm/min

https://i.imgur.com/gd3yiQq.jpg


Finish pass done

https://i.imgur.com/HjjWD2W.jpg


Flipping for reverse chamfer on the seal holders:

https://i.imgur.com/JWvIGQH.jpg


Shame I need to re-do them!


Anyway, in happier news my RoverCNC spindle mount arrived today and it's a beauty... I ended up paying almost as much in shipping as in cost of the part sadly, but it was worth it - so much nicer than the extruded type mounts you see everywhere, this one has been machined from a solid block. You can see the difference in how smooth the bore is and just laying down the spindle in the bottom half gives a super snug fit with no wobble. Should be a great improvement compared to the one on my current machine.

https://i.imgur.com/Q14iHyx.jpg

https://i.imgur.com/4Nhjsqf.jpg

Mmmmm... chunky.


I also had a bit of a brain wave (or rather realised I was being stupid as usual), there was absolutely no need to separate the rail wiper seals from the central seal given that I was 3D printing them. I joined them up into one big unified seal instead which is a much better idea.... Nailed the printing, I made the error of not accounting for thermal shrinkage which is why they were a touch tight on the rails. A scale factor increase of 0.7% in X and Y put the dimensions spot on the money once the material had cooled and they are now a beautiful fit.

https://i.imgur.com/HhVZIfr.jpg

https://i.imgur.com/yyZcxzh.jpg

https://i.imgur.com/V0hAfgM.jpg



Quick test with the rails:

https://i.imgur.com/FO4wHqM.jpg


And top plate

https://i.imgur.com/QXYzceC.jpg

Great work Zeeflyboy. Seals are looking really good too

BAD@SS!!! :cool::cool::cool:

Quote:

---

Originally Posted by Nickhofen

BAD@SS!!! :cool::cool::cool:

---

Damn autocorrection, I wanted to write "It looks grate"!!!

When I look at yours and routercnc work I don't think you're putting my work to shame I think I would have to climb a very long ladder to get as high as shame ha ha ha.

You make it look easy and as my mate said when I showed him your thread why don't I just do it like you do lol.

Cheers guys!

Quote:

---

Originally Posted by Desertboy

When I look at yours and routercnc work I don't think you're putting my work to shame I think I would have to climb a very long ladder to get as high as shame ha ha ha.

You make it look easy and as my mate said when I showed him your thread why don't I just do it like you do lol.

---

I make it look easy? Despite my constant messing things up lol?

Quote:

---

Originally Posted by Davek0974

Fair-do's to you, just thought i'd throw it out there ;)

---

Absolutely, I never even knew they existed so glad you mentioned them.

Sometimes I wonder if I should do fewer but less incremental updates - not sure which you guys would prefer?

Anyway, for now a little extra work done today.

I've done a few tweaks to the Z-axis design after having a long think about how it's going to be assembled and aligned on the machine. To that end I've added an eccentric bushing to the top of each carriage mount and a 6mm dowel pin at the base to act as a pivot point. The idea being that I can install the backplate on the machine, lining it up square to the gantry arm. One dowel pin will provide a hangar while installing and ensure its central on the slider.

Then I can use a dial indicator to align the right carriages to a machinist square based off the bed, which will ensure the rails are aligned 90 degrees to the bed in X, then use those to dial in the left carriages.

Only had time to do one side of the carriage mounts today but It came out very nicely and for once I managed to make a part without messing anything up. When it cam to reaming the dowel pin hole I just had a very low feed rate and span the spindle by hand... I'm thinking there must be some sort of cunning arrangement I can come up with in future to spin the spindle slowly using a separate motor and some HTD belt/pulleys for things that need super low rpm like reaming/thread milling.

Anyhoo:

Top side finished

https://i.imgur.com/fAtblWt.jpg


Flipped and bottom side done (used dowels to align with Y, then probed the reamed hole to determine zero)

https://i.imgur.com/l9pgsQa.jpg

https://i.imgur.com/aY6zzTg.jpg

https://i.imgur.com/LhAPVTv.jpg

https://i.imgur.com/qlwkofb.jpg


I also designed a top seal for the motor mount, took a few prints to get it perfect as the CAD model of the motor mount isn't entirely correct in the non-critical dimensions:


https://i.imgur.com/kMXVU28.png

https://i.imgur.com/TTPqwKb.png

https://i.imgur.com/aakTBHa.jpg

https://i.imgur.com/ReLzVCl.jpg

There are some supersexy parts there..
The vipers are a great idea but looks better still.
Im also envious of the spindle bracket!

Well.. I know what I want for mk2 of my machine :D

Skickat från min SM-N910C via Tapatalk

Lovely work once again well done.

I would say release updates when you are ready and at a rate that feels enjoyable. It's easy to think everyone is tapping their fingers wait for new information but you are doing this for free and for fun so don't feel pressurised.

Awesome work.

Some questions.

What 3D printer / material are you using?

In terms of your bed, you always seem to have screws for workholding in the correct places. Are you drilling the holes (or milling them) and then drilling / tapping into whatever material your bed is made from on your mill? I struggle with workholding at time yet you make it look easy.

Thanks

I'm using my trusty old makergear m2... I've had it for about 5 years now and it's still churning out lovely prints. I actually designed myself a new super duper printer which I'll make one day once this CNC machine is done, but that's really just because I want a bigger beast with quad extrusion and dual independent heads. Oddly enough makergear just announced their new version that does have dual independent print heads, but I would still want the larger build platform to make best use of them (I love the idea that you can print two sets of the same items simultaneously, effectively doubling output of parts if you need more than one of anything).

Material is some stuff called Cheetah by ninjatek. It's a flexible rubbery material a bit like hard skateboard wheels, 95A on the durometer scale... fairly easy to print with if you have a direct extrusion head. I believe it even works with some bowden printers.

Workholding wise for these big pieces I have been using a 12mm sacrificial sheet of SRBP, skim it level and then where the parts have suitable holes I run a "jig drill" drill cycle through into the bed that then allows the hole to be tapped and a screw inserted without moving the part. For the exterior clamps I either try to find a previous hole that works or just drill a new hole and tap. I keep going until either I skim down too far or it becomes like swiss cheese and then I replace with another sheet.

It's not the cheapest option I'm sure (a sheet that size costs around 30 quid) but it's a wonderful material for stability, machinability, coolant resistance and accepting threads/dowels etc.

Thanks for that. Can you explain a bit more about how you might do the drilling / tapping into the SRBP in one step without moving the part?

Thanks

Nothing particularly clever I'm afraid... I took some more photos today of the second carriage mount so perhaps an explanation with the pictures is best.

So on this part for example, I have some 5.4mm holes in the part for M5 screws.... After I've finished drilling/milling those holes while the part is held down using external clamps I would add an extra drill cycle using a mm drill bit on the holes I want to use as a fixture, setting the hole top as the stock bottom and the hole bottom as stock bottom minus eg 10mm.


External clamps, run the milling/drilling of internal holes to be used as hold down points, then run jig drilling cycle.

https://i.imgur.com/i5WkeIS.jpg


Once that's done I used compressed air to blow the SRBP dust clear, using a hand drill I whizzed a spiral m5 tap down through to the bottom of the hole and again give another blast of compressed air to clear the hole.

While the part is still clamped down with the external clamps, I then find some appropriate length screws (important that they aren't too long, thus preventing proper tightening down of the part, but you want to make sure they at least get a good 5-6 turns of engagement so that you can snug them down tight. It pays to have a nice assortment of various length screws in typical sizes - m4, m5, m6, m8 is what I tend to use.

Once those are tightened up you can remove the external clamps which lets you run the remaining cycles... just be sure to check your tool paths to make sure it isn't going to try to mill out those holes again as it'll find a bolt there of course (adaptive can be a little bugger for that, just make sure you have ticked "rest maching" and selected "from prior operations" so that it doesn't try to remove the same material twice).

https://i.imgur.com/sNfXzsR.jpg

https://i.imgur.com/mPfvENz.jpg

https://i.imgur.com/aPBiLO8.jpg


If you've thought about it a little before hand and the part is suitable, you can use the same holes to hold it down on any bottom side operation, I like to use 6mm dowel pins in the bed to butt the part up against to ensure it's aligned to the axis.

With it held down, I find a suitable area to probe to define zero again

https://i.imgur.com/IDjg2bN.jpg


If possible I do a quick gross error check to make sure zero looks good:

https://i.imgur.com/xhbOkDD.jpg


And then run the rear operations:

https://i.imgur.com/CjNauu1.jpg

Thanks, excellent explanation.

I suspect you can also just set your retract height higher than the bolt height. It might waste a bit of time but better than cutting into the metal etc.

Certainly easier if you do rest machining or similar as you have said but you never know what path it will take when it crosses over. Always good to watch the CAM 'preview' before actual cutting IMHO.

Yes absolutely, make sure if the bolts are sitting proud of the surface you set an appropriate retract height. I actually always just set it at 25mm as a matter of habit, it doesn’t waste much time at all as all moves back down to the top height are done at rapid’s speeds.

I just got a piece of SRBP to try. It's incredible that it's made out of resin and paper, it looks really tough and quite heavy. I only got a 400x300 piece, in 15mm, as it's quite expensive, I think you use larger sheets?. I am guessing that Tufnol is a brand name, but the same thing?

I just wanted to ask roughly how thin does it get before you discard it, with regards to having enough thread left in the holes with sufficient strength to clamp the piece, 8mm or so? If you use M5 bolts, I suppose you need a good 5mm of thread? Secondly, I assume that you don't skim it every time you cut a new piece, provided you have enough of a flat, clean area left for the next piece to sit flat, is that right? Also, what's your favourite tool for skimming the SRBP? Does it machine similarly to Delrin? (the only plastic I have machined).
Keep on posting about your progress, the more the merrier:)

Edward

Quote:

---

Originally Posted by Edward

I just got a piece of SRBP to try. It's incredible that it's made out of resin and paper, it looks really tough and quite heavy. I only got a 400x300 piece, in 15mm, as it's quite expensive, I think you use larger sheets?. I am guessing that Tufnol is a brand name, but the same thing?

I just wanted to ask roughly how thin does it get before you discard it, with regards to having enough thread left in the holes with sufficient strength to clamp the piece, 8mm or so? If you use M5 bolts, I suppose you need a good 5mm of thread? Secondly, I assume that you don't skim it every time you cut a new piece, provided you have enough of a flat, clean area left for the next piece to sit flat, is that right? Also, what's your favourite tool for skimming the SRBP? Does it machine similarly to Delrin? (the only plastic I have machined).
Keep on posting about your progress, the more the merrier:)

Edward

---

Its pricy alright, £60 for my size machine. That said, if its makes machining a lot easier, its worth it. Also keen to understand if there are variations of this material that might be worth looking at.

I paid £44.32 including the £15 for UPS, for the 400x300 piece. I guess if you ordered a few pieces it would just be the one-off transport fee. At least they provided an invoice, so I can discount it off my tax as a legit expense.

They also call it Phenolic Sheet.

Edward

At prices of Tufnol I'd glue it to a 12mm sheet of mdf then you can mill through the whole lot screw wasting any.

If you have issues with losing 12mm of travel on the Z then you really have issues lol

Quote:

---

Originally Posted by Desertboy

At prices of Tufnol I'd glue it to a 12mm sheet of mdf then you can mill through the whole lot screw wasting any.

If you have issues with losing 12mm of travel on the Z then you really have issues lol

---

Problem is that MDF absorbs fluid and 'pulls' apart.

Yep, MDF is pretty duff for metalwork, great for woodwork.

At these prices, has anyone priced up a slab of aluminium?
Its pretty reasonable in 12-15mm thicknesses.

Quote:

---

Originally Posted by Davek0974

Yep, MDF is pretty duff for metalwork, great for woodwork.

At these prices, has anyone priced up a slab of aluminium?
Its pretty reasonable in 12-15mm thicknesses.

---

Oddly, was thinking the same. £86 + VAT + Del for 12mm tooling plate at 650 x 450. Normal plate is still £75.

Yes, similar prices. So what's the attraction? Is Tufnol easy to skim, I bet it skims like butter and really fast, probably quite messy, though not as messy as MDF and harder?

Tufnol is a brand name, Kite is their equivalent product. Tends to be a bit more pricey than the generic SRBP... I've been buying attwater brand from ebay.

As for why it's better than alu, it's probably not really! It does skim very quickly and easily with minimal mess (I skim 0.3mm at 6000mm/s using a single flute 10mm cutter)... I like to cut past the work piece in general so I set a cut through of around 0.2mm which then gets completely cleared out at the next 0.3mm skim.

The main advantage to my mind is that it's softer than alu so more forgiving of plunging down into it quickly so for drilling/tapping it's quicker. Also if cutting CF/FR4/G10/whatever then the fishtail burrs I use for that wouldn't like cutting into alu below the piece but they don't care about cutting into SRBP.

Alu can also leave a bit of an upward edge/burr where it's been cut which might mess with your perfect level bed until the next skim. SRBP doesn't leave any burr that I can see.

Both would be perfectly valid, I just tend to use SRBP for the above mentioned reasons. It is also cheaper than tooling plate... eg a board of 600x400x15mm is £50.46 vs £99.36 for the same size of tooling plate from Alu warehouse (both including VAT). That's half the price... adds up when you consider it's a sacrificial board that your machine will consume over time.

I used a 12mm board which is a bit cheaper than the 15mm... I think it will be too full of holes before I skim it down to a height that's unusable, so there's probably a balance to be found between over-paying for a thicker board that won't be used to it's potential before becoming too full of holes. Will depend on how big your bed is and how hole intensive your work is!

It is also worth considering that you don't necessarily need a piece to cover your whole bed, only big enough for the largest piece of work you need to hold down.

Thank you Zeeflyboy, you are very helpful and I see your logic. The piece of SRBP that I got has slight burring at the edges from the cut, easily removed with a light touch of sandpaper. I also got the same Attwater brand.
Edward

Quote:

---

Originally Posted by Zeeflyboy

Tufnol is a brand name, Kite is their equivalent product. Tends to be a bit more pricey than the generic SRBP... I've been buying attwater brand from ebay.

As for why it's better than alu, it's probably not really! It does skim very quickly and easily with minimal mess (I skim 0.3mm at 6000mm/s using a single flute 10mm cutter)... I like to cut past the work piece in general so I set a cut through of around 0.2mm which then gets completely cleared out at the next 0.3mm skim.

The main advantage to my mind is that it's softer than alu so more forgiving of plunging down into it quickly so for drilling/tapping it's quicker. Also if cutting CF/FR4/G10/whatever then the fishtail burrs I use for that wouldn't like cutting into alu below the piece but they don't care about cutting into SRBP.

Alu can also leave a bit of an upward edge/burr where it's been cut which might mess with your perfect level bed until the next skim. SRBP doesn't leave any burr that I can see.

Both would be perfectly valid, I just tend to use SRBP for the above mentioned reasons. It is also cheaper than tooling plate... eg a board of 600x400x15mm is £50.46 vs £99.36 for the same size of tooling plate from Alu warehouse (both including VAT). That's half the price... adds up when you consider it's a sacrificial board that your machine will consume over time.

I used a 12mm board which is a bit cheaper than the 15mm... I think it will be too full of holes before I skim it down to a height that's unusable, so there's probably a balance to be found between over-paying for a thicker board that won't be used to it's potential before becoming too full of holes. Will depend on how big your bed is and how hole intensive your work is!

It is also worth considering that you don't necessarily need a piece to cover your whole bed, only big enough for the largest piece of work you need to hold down.

---

I agree with this. The other option as a middle ground might be some good plywood. Ive got some and will use it and see how it goes.

So re-visted my end plates with the correct size stock this time...

I also tweaked the designs a little, adding a port for the limit switch wire to the top plate and changed the bottom plate to accept a standard FF12 bearing mount (along with some room for adjustment).

(correct size!!!) stock:

https://i.imgur.com/DotATAO.jpg


First op done and bolted down

https://i.imgur.com/PjcazaH.jpg


Top side ops done

https://i.imgur.com/xbqOgX1.jpg


Bottom sides:

https://i.imgur.com/6ay7VyN.jpg

https://i.imgur.com/W3PN5Y4.jpg

https://i.imgur.com/oblZPvO.jpg


And the back section of the Z-axis is looking a bit more complete! Still needs limit switch installing, side plates and seals machining up, then I can move on to the main front plate and tramming plate.

https://i.imgur.com/DGTvjjs.jpg

https://i.imgur.com/f6tbQ39.jpg

https://i.imgur.com/0oBHgKo.jpg


Good view of top seals:

https://i.imgur.com/mQs69jp.jpg

Quote:

---

Originally Posted by Zeeflyboy

So re-visted my end plates with the correct size stock this time...

I also tweaked the designs a little, adding a port for the limit switch wire to the top plate and changed the bottom plate to accept a standard FF12 bearing mount (along with some room for adjustment).

(correct size!!!) stock:

https://i.imgur.com/DotATAO.jpg


First op done and bolted down

https://i.imgur.com/PjcazaH.jpg


Top side ops done

https://i.imgur.com/xbqOgX1.jpg


Bottom sides:

https://i.imgur.com/6ay7VyN.jpg

https://i.imgur.com/W3PN5Y4.jpg

https://i.imgur.com/oblZPvO.jpg


And the back section of the Z-axis is looking a bit more complete! Still needs limit switch installing, side plates and seals machining up, then I can move on to the main front plate and tramming plate.

https://i.imgur.com/DGTvjjs.jpg

https://i.imgur.com/f6tbQ39.jpg

https://i.imgur.com/0oBHgKo.jpg


Good view of top seals:

https://i.imgur.com/mQs69jp.jpg

---

Excellent work as usual.

It's so beautiful that I think I'm gonna cry! ;)

Skickat från min SM-N910C via Tapatalk

The vacuum pods on our smaller machine are made from Tufnol / SRBP (Use the stuff from DirectPlastics), i think its absolutely horrible stuff to work with, stinks and iirc some types can be carcinogenic. On the larger machine the vacuum pods are machined from a dense type of Phenolic Plywood, much nicer to work with and doesn't appear to be affected by moisture, the stuff we get is 80mm thick.

On a separate note this machine is epic can't believe i only just found it! That Z Axis is a thing of beauty!

Alex

Tufnol is a great stuff to work with. The same settings you use for hardwood just slow feed rate to 1/3 and machines perfectly.

Thanks chaps.

Alex - the attwater SRBP msds seems pretty benign.. I would be surprised if it was any worse than MDF for you anyway! http://www.attwater.com/downloads/sr...lth-safety.pdf

I think as with all these things it's best to avoid inhaling any dust anyway.


Made the front plate today, bit more of a challenge to hold down as it doesn't have sufficient through holes... instead I had to spilt the operations up a bit.

First setup - machined the ends and the back side for rail mounting holes, HD16 mounting pattern and some temporary alignment block holes to make sure the first rail is straight to the edge of the plate.

https://i.imgur.com/8hBh1mL.jpg

Then re-clamped and ran the side machining:

https://i.imgur.com/hAg0tht.jpg

https://i.imgur.com/OnergjD.jpg


Drilled a few 6mm dowel pin holes to butt the piece up to when flipping for top side operations:

https://i.imgur.com/x7AR5Fp.jpg

https://i.imgur.com/o7vzf1n.jpg

https://i.imgur.com/S9Io4Hj.jpg


Unfortunately I don't have any correctly sized m5 bolts for mounting the rails. Amazing - seems no matter how many screws I have on hand, I never have enough of the correct size!

Of course you don't have the right sized bolts that's because I have the right size ones that you want and you have the ones that I want ha ha ha.

Because god hates CNC builders otherwise he wouldn't have let them design 15mm hiwin greasing points lol.

I hear you Zeeflyboy and Desertboy.

That sinking feeling when you realise the only screws you have in the draw are too long and they have to be cut down and the ends dressed. Still, it beats being too short and the job not progressing until the postman has arrived.

Maybe we need some sort of online swap-shop !

Just to follow up with the Phenolic Plywood, tested it by leaving some water on it for a few hours but it didnt seem to absorb much - if any. I suppose a layer of lacquer would totally seal it.

Attachment 22952

Attachment 22953

Thanks

Alex

EDIT: Not sure why the site keeps rotating my pictures 90Deg -_-

good stuff :)

So another day another part... the Z-axis (or should that be Zee-Axis? :yahoo:) inches closer to completion. At this rate I may be finished by mid 2018.

Today is the turn of the tramming plate.

https://i.imgur.com/ziCvGMr.jpg

https://i.imgur.com/0O6nQmU.jpg

https://i.imgur.com/coxwuJ0.jpg

https://i.imgur.com/qTfStCs.jpg

https://i.imgur.com/yqaEFQm.jpg

https://i.imgur.com/bQ8CMCj.jpg

Fitted to the existing parts of the Z-axis ( needs a shoulder bolt in top right and eccentric bushing in top left) and showing full up and full down travel positions:

https://i.imgur.com/MYtY1bm.jpg

https://i.imgur.com/g3UL2j4.jpg

https://i.imgur.com/nRVYucB.jpg

https://i.imgur.com/ILYo0Tq.jpg


So next up really I need to get around to making the eccentric bushings, and I also need to knock up a little adjustable Z-limit trigger piece. Then it'll be the turn of the side plates to finish off the Z-axis completely.... I decided to allow myself a little "pointless" flair on the side plates and will try to make some inset CF pieces just for aesthetics.

https://i.imgur.com/60QMPkk.jpg

Now that I can see where you've placed the motor mount, it gives an idea of the total height allowed from the nut to the base.

This is the one thing where I have agonised when messing about with my design. It's difficult to see in yours because the pic is not head on, but it looks like the spindle nut base falls about parallel to the edge of the extending plate, maybe slightly lower. One thing that I am sure you have thought about is that the clearance of the sliding plate is above the holding clamps for the part, in cases when you are cutting something deep using the full flute length, you don't want the sliding plate to touch the clamps.

Edward

Actually that's just the angle of the pics, I designed it with the idea of having the bottom of the spindle nut approximately 1cm below the bottom of the mounting plate for that very reason. Obviously it's fairly easy to adjust to taste simply by moving the spindle slightly lower/higher in the mount.

So I had a go at creating my first eccentric bushing this eve. Seems to have come out quite nicely given that I have no idea what I'm doing!

I started off with some hexagonal stainless steel stock, and installed my 4 jaw chuck on the lathe. First job was to turn down to a diameter I could measure off to calibrate the scales.

https://i.imgur.com/SBStKM9.jpg

Then turned down to 11.99mm

https://i.imgur.com/QJq2RY2.jpg


I was designing it to the specs of a specific commercial product as before I got the lathe I was intending to buy them. So I had to copy the slightly odd offset of 1.07mm from centre:

https://i.imgur.com/DpegfED.jpg


Then drilled out the bore, flipped and faced the top side.

https://i.imgur.com/pCcRJD9.jpg


End result:

https://i.imgur.com/pEHgow8.jpg

https://i.imgur.com/VhYtHen.jpg