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  1. #421
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Hi Routalot- Theres a bit of discussion and answers in this thread on vibration of ballscrews.

    https://www.cnczone.com/forums/diy-c...gineering.html

    Peter

  2. #422
    Join Date
    Aug 2014
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    232

    Re: Designing new Router called Maximus

    Quote Originally Posted by RCaffin View Post
    It's when your cutter goes that colour that you know you are really in trouble!

    Cheers
    Roger
    I once made the mistake of turning off the coolant so a visitor could get a better photo of some titanium being turned, the tool was red in seconds. Oops.

  3. #423
    Join Date
    Jun 2010
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    4252

    Re: Designing new Router called Maximus

    I once made the mistake of turning off the coolant so a visitor could get a better photo of some titanium being turned, the tool was red in seconds. Oops.
    Without knowing any details, I think that means you were cutting too fast and maybe not aggressively enough. Ti is funny stuff: treat it gentle and it will get hot, hard and bite you. Rip into it (and keep it COOL) and all will be well. Yes, I have some experience with Ti.

    Cheers
    Roger

  4. #424
    Join Date
    Aug 2014
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    232

    Re: Designing new Router called Maximus

    Quote Originally Posted by RCaffin View Post
    Without knowing any details, I think that means you were cutting too fast and maybe not aggressively enough. Ti is funny stuff: treat it gentle and it will get hot, hard and bite you. Rip into it (and keep it COOL) and all will be well. Yes, I have some experience with Ti.

    Cheers
    Roger
    This part has a long taper on it which is turned in one operation, the cut is deep at the end. It's fine with coolant, lots of it. I make sure to get a decent depth of cut or tools die quickly, especially centre drills, which causes the next drill to break, then the tap that follows.

  5. #425
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    Jun 2010
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    4252

    Re: Designing new Router called Maximus

    You don't actually need flood coolant with Ti. I use pulsed MQL (3 parts kero, 1 part olive oil, ~0.5 sec pulse every ~10 sec) with an air blast (which does cool) for 6Al4V.
    Attachment 436266
    Works fine with sharp carbide cutters. If you are careful, you can use sharp new HSS as well.

    Cheers
    Roger

  6. #426
    Join Date
    Aug 2014
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    232

    Re: Designing new Router called Maximus

    That's interesting Roger, thanks, if I need to cut Ti sheet on the router I'll look into it. Currently the only sheet big enough to use the router is aluminium, I use WD40 on that. Anything smaller than 1000 x 500mm will fit in the
    Bridgeport which has flood lube.

    My lathe is designed for soluble oil, although it can use neat oil like most swiss lathes. Some years ago we got a big sub-contract job from someone who was using neat oil in theirs - until it caught fire. Not a pretty sight in an epoxy-granite machine.

    This is a video of the same type, slightly smaller capacity :




  7. #427
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    Jul 2018
    Posts
    6254

    Re: Designing new Router called Maximus

    Hi All - Been a while since I worked on Maximus. In review here's the wash-up:

    1) Convert to ballscrew design - driven by cost and client requests. ATL belt is more cost then using C7 ballscrews. Customers are unsure about belts. Laser people are very comfortable with belts...
    2) Inquiries continue to ask for high Z axis and to cut aluminium. This is tricky and even though the high rail design answers some of this it does not solve all of the issues around this request
    3) There is concern over the timber machine base, although the timber workers accept it easily

    So:
    1) I've designed a half sheet machine called YaG that is ballscrew driven and follows on in Maximus' footsteps. YaG is for timber workers with no mention of cutting aluminium and the high rail plywood machine base is accepted as OK.
    2) I have been developing a benchtop mill and that got a long way down the track. BUT people want bigger beds then a column mill can handle so I started looking at gantry mills. But then I'm back to the issues created by high Z height...
    3) Then I came across lifting gantry mills and this configuration solved many problems. So I decided that all my future Mills and Routers would be lifting column designs.
    4) So I shall need to design/build a lifting Gantry router and a Mill
    5) I have been playing with Epoxy Granite like materials and have settled on a process and material. a) parts will be infused fibreglass (stiff, cheap and damp) as I have years of experience with this and the material is fully characterised making FE work accurate. It will be thick skinned maybe 10-15mm so it can be machined or drilled and threaded. ie no inserts needed. I have many years and tests done to qualify thread pull out etc...Things like the Mill machine base can be moulded in one piece and be stiff, medium weight and fluid impervious
    6) The inside or core of the parts will be infused steel fibre or steel shot (Tetrium-S) . This is dense (4400kg.m3) damp and cheap. Plus it can be machined easily vs sand and other mineral or ceramic fillers which need diamond type tools.
    7) So large parts are a two step process, infuse skin then infuse core.... then post cure, then finish machine (did I say 4 steps?)

    So Maximus didn't make it to build but laid the path for YaG which I started building this week. YaG will cut aluminium and can make the moulds for future machines. By the way I sold my half sheet development router Scoot-Beta. This gives me the $$$ and space to build YaG. Build one, sell one, build another is the current mantra....

    Maximus will be superceded by Max2 a half sheet lifting gantry router. The mill will be called Milly and will be a full composite lifting gantry design. Looking forward to that project.

    Best Regards to all interested Peoples & keep safe in this odd environment. Peter

  8. #428
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    Aug 2014
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    232

    Re: Designing new Router called Maximus

    Nice to see you posting again.

    With the cost per length of the rails fairly small, would it be worth extending the rails to the full outside size of the machine, to allow the carriages to be placed further apart ? It might give an improvement in rigidity for little cost.

  9. #429
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    H Zorbit - Which rails? The YaG image has short rails as it has not been detailed out. They do extend to the rear of the machine. They do not have to come to the front of the machine as the Z axis stacks forward. I have been posting on other threads. The EG thread and the Brevis HD thread which became YaG... Maximus is pretty much done and will fad into historical obscurity...Peter

    With pressed metal fabrication holes have to be certain distances from the bends to prevent them stretching when bent. This turns out to be a major issue trying to keep things small or have holes close to edges and bends (such as bearing spacing). The solution is post drilling but this can be just as much cost as the part due to so much touch labour $$$. This is one reason to move to composites or billet machined parts as then holes can nearly be anywhere.

    If its the gantry rails you are talking about, the limiting factor is the Z axis width, it collides with the "wall" so no point going wider with the rails unless you make the machine wider in 60mm increments. Its currently wide enough for a full sheet 1220mm plus 110mm for clamping area so no value going wider...Its quite a big geometric puzzle.

  10. #430
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    Jun 2010
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    4252

    Re: Designing new Router called Maximus

    Prediction:
    You will eventually have to switch to steel inserts for the bolts. Yes, I know you mentioned that you can get good pull-out strength with composites, but that is for a static situation and mostly when new. Mills vibrate, and the composite will gradually, over time, abrade away at the threads. That can be very bad for the rep.

    Fwiiw, On the parts I make which could be described as 'pressed metal', I bend first, jig and then machine. In the long run, it is worth the effort (at least for me).

    Cheers
    Roger

  11. #431
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Experience:
    Over many years and many tests in industrial environments static and severe dynamic eg 25 year endurance test for elevated work platform structures A) I wax the bolts and set the bolts with epoxy or loctite after the first pull down. I prefer 5 min epoxy but most people are familiar with thread lockers. They release easily when/if needed if waxed and hold tension forever as best as I can determine.

    B) My machines are designed for production so cost reduction is the driving mantra vs manual operations. If I'm doing something for myself I'm happy to do complex or weird stuff to get an outcome but production machines have to be simple and have the least amount of labour involved.

    In the 25 year simulated endurance test the production staff where pessimistic about one area where I had screws into the end grain of a laminate. At 8 years in ( ~1 week of 24 hour cycles at 175% max load) the machine started deflecting more then usual so it was pulled down and we found the bolts had broken but had left the threads intact so we replaced the bolts and kept going. Nearly to the same cycles the bolts broke again so again we changed the bolts and they broke again just before the full time on the rig. I trust composites more then metal when it comes to fatigue. Cheers Peter

  12. #432
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    Jun 2010
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    4252

    Re: Designing new Router called Maximus

    I wax the bolts and set the bolts with epoxy or loctite after the first pull down.
    Ah - that is different from just tapping a hole in a composite. Very different in fact. I can imagine that working OK.

    Cross-country skis usually have a very light wooden core, although sometimes a light composite, with a thin synthetic shell. Now try screwing the boot bindings onto the skis and having them stay on. Very difficult. So we drill the hole, thread it (usually a coarse self-tapper), then add slow epoxy resin into the hole, then screw the bindings on. That works fine: the epoxy distributes the load. It does make it difficult to remove the bindings later on if you break the ski, but of course we 'never do that'.

    Cheers
    Roger

  13. #433
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Hi Roger - Many years ago I worked at a ski field as a ski mechanic. So know about that. The undo trick is to use a soldering iron and warm the head a little and it unscrews with ease. Cheers Peter

    I prefer 5min epoxy as it has an aggressive hardener and will set in very small amounts and cold conditions. Being formulated for 50/50 also makes it easy to measure out by eye even two match head amounts will work. Whereas "normal" epoxy at about 25H/75R means you have to measure a reasonable amount to get the ratios right so you tend to waste more. I have small scientific scales but 5min is easier.. Peter

  14. #434
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    Jun 2010
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    4252

    Re: Designing new Router called Maximus

    Hi Pete

    Yes, I know about using heat. Been there when changing bindings.

    The 24 hr Araldite I use is a 50:50 mix. I dare say they made it that way for simplicity for the average user.
    What brand has a 25/75 mix? Just curious.

    Cheers

  15. #435
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Araldite as bought from Bunnings say is a thixotroped epoxy made simple to mix and use for bonding various things. Laminating resins and infusion resins have less additives so are closer to the stoichiometric active constitutes. I use atl kinetix R118 a lot and its 25H to 100R sorry last entry I used 25/75 but its usually ratioed as 100units of resin to X units of hardener. So its actually less then 25/75 more like 20/80 ratio. This is similiar to many other epoxy mixes. Cheers Peter

  16. #436
    Join Date
    Jan 2008
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    1523

    Re: Designing new Router called Maximus

    The Kinetix looks like nice low viscosity resin. Fairly pricey from what I can see of available prices (>$800 for 22.5kg).

    What do you think of the below resins:
    https://trojanfibreglass.com.au/prod...clarity-resin/
    https://trojanfibreglass.com.au/prod...-resin-51-2-2/

    Also, do you have experience with vinylester resins? A number of papers suggest it performs between polyester and epoxy in polymer concrete applications and it's cheaper than epoxy.
    7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)

  17. #437
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Hi Pippin - Trojan epoxies are thicker then the kinetix resins and are not intended for infusion. Infusion is my main process. I have spoken to Trojan and some of their customers infuse with their resins. The price is good if you need a clear laminating resin. Vinyl esters are very good for many applications. Its main issue is the same as polyester resin, it shrinks about 8% by volume. This is because it is supplied with an excess of styrene in it, by excess I mean more than is required for the polymerisation of the resin. I believe this is done in case some styrene is lost during transport/storage or use prior to polymerization.

    Over time this excess desorbs from the laminate and hence shrinkage occurs. Its about $10AUD/kg vs epoxy up to $20AUD plus/kg for specialist epoxy.

    Been using PE-VE-EP and PMMA resins for over 30 years.

    So if you use VE for polymer concrete in machine parts, the part will change shape in the first few months of use. If you use it to make billets, post cure it say 80degC for 8 hrs (which removes the excess styrene plus fully cures the resin) Then machine to size it will be stable (technical maybe). But most people can't do this. Epoxy is used for EG because it has very low shrinkage on cure. 100% "solids" epoxy has no solvents so has nothing in it to desorb. Epoxy is a 100% stoichiometric reaction so its shrinkage is from molecular reorganisation which is volumetrically very small and its thermal shrinkage from exotherm temp to ambient. In polymer concrete if the filler is of high packing factor (60-80% solid) then the overall shrinkage is very very small. I have blocks here I made over 15 years ago and the epoxy ones are still flat as far as I can tell. I had one of VE that cupped even though I fully cured it prior to blocking. So for EG or PC or machine parts I'd go with epoxy.

    You can get tooling resin that is polyester based with mineral fillers with very low shrinkage. It also uses PET fillers that expand when heated compensating for the PE shrinkage. But they are just as expensive as epoxies so I usually don't go that way. The epoxy granite thread is huge and complex.... Peter

  18. #438
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    Jan 2008
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    1523

    Re: Designing new Router called Maximus

    Thanks for the details.

    I don't foresee doing infusion myself, will be mixed and poured with the aggregate.

    Do you think the trojan epoxy will be reasonable for mix then add to the mould?

    I'm planning on just tamping down the mix. I know some go to great lengths to vibrate the mould etc. The way I see it, a bit of porosity doesn't matter. We are building for stiffness which means large sections that will compensate for a few % off perfect compaction.

    I thought was much with vinylester but good to get your knowledge. Epoxy it remains.
    7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)

  19. #439
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    Jul 2018
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    6254

    Re: Designing new Router called Maximus

    Hi Pippin - From memory last time I did a supplier comparison Trojan did well with cost. Trojan will be fine for a mix and pour use slow hardener. I agree porosity does not matter. Dry your fill. It contains lots of water and epoxy does not like water. Either heat it in an oven or blow hot air through it or something. Water really mucks up various mechanics like mixing, "wetting" and curing. In the infusion process you can see the water coming out of the dry stack and I will leave things under vacuum for 2 hours to dry it sometimes. Do a trial mix in a known container size and then fill with water to estimate void = resin required. Weigh everything. I think you have been in on such a conversation elsewhere? Happy to help, ask away. Peter

  20. #440
    Join Date
    Aug 2014
    Posts
    232

    Re: Designing new Router called Maximus

    Peter, you mentioned Tetrium-S, so I had to google it. I see it's your baby, so I guess that's why you didn't put a link to it.

    https://cncrouterkits.com.au/tetrium/

    It looks very interesting. I have a load of fine titanium and stainless steel swarf, which I had been intending to mix with refractory cement to build some pizza ovens with, but an experiment with resin might be fun. I guess anyone wishing to give it a try could just buy some wire wool.

    Is it possible you could share some more information on the method ? I'll understand if it's proprietary at this stage.

    Thanks,

    Z


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