Hi Ard- Do you remember which one? saddles have so many issues!! Peter
hey Pete, you mentioned you figured out the saddle issue, I'm really interested in your solution...
Hi Ard- Do you remember which one? saddles have so many issues!! Peter
I think it was about the newest one, the M1 clone saddle. I know, I hate saddles. A good saddle is no saddle or at least a metal monoblock and fabrications are such a gamble without heat treatment. Wish someone smarter just jumped in and figured out vsr with arduino/raspberry pi and ended this nightmare for all of us.
You have shown a triangular gantry is the go in the past.
DMG DMU 600 has a triangular gantry
https://www.aeroexpo.online/prod/dmg...363-63532.html
Hi Pippin - Now that's a gantry!! You could convert that into a tiny home and rent it out...
Hi Ard - Ahhh yes the M1. I took the stand that the Mill (Milli) had to be made in aluminium (or a metal laminate) and machined on a big mill to get it accurate. I like the Mori - M1 arrangement but its a typical saddle with pockets for the bolt access to the cars and its cars are nearly on top of each other. The usual issues with saddles. So I placed the cars on the sides of the ram (some call it the overhead arm) This allows access to the cars bolts, no pockets and the lands can be machined in one go from above. Assembly could be difficult but I'll work thru that in time.
And a lifting gantry design removes the saddle so many advantages there. Plus now I'm looking at printer boards with 8 axes, the extra axis control seems to be solved so lifting gantry maybe a better path....
ah side mounting, gives you more stiffness too, clever. well there are other ways to get rid of the saddle...yes I do have a thing for the moving column
Hi Pippin - Re: Mori and it uses linear motors excellent!! Peter
I have a thing for linear motors too, they're badass, it's like magic. I'm exploring how expensive it would be to use them, I'm in touch with 2 chinese companies that make them. One of them is still developing higher N forcers so maybe I could get them at a bargain. Right now a C3 ballscrew w/supports and servos would go for $2000-2500 depending on the servos.
You could technically just get the forcers and make the stators yourself but the issue remains with the drives. Every now and than hiwin forcers appear on ebay like: https://www.ebay.de/itm/254241865468 but the compatible ED1 drives almost never, and new ones are insanely expensive. I saw a used one for +$2000 once.
Hi Pete, this might be of interest to you, 9 axis millturn running on Duet3 a 3d printer controller.
https://forum.duet3d.com/topic/31653...essional-build
Hi Ard - Thanks - I think duet is going to make inroads into cnc world. Thanks for finding that. Peter
Hi All - The Milli thread has been slow but I have been trying to finalise Frankie so it can leave the workshop so I can start the next machine! But another thread has pushed me down a path and Milli has woken up again. Sika have a high modulus grout which I shall assume I can get here. I shall put in an enquiry to check I don't have to buy 35T of it. Sika-3350 E-56GPa. Plus they have a self levelling grout... My rule about a part being no more than 50kg has stymed me so I think the base has to be two pieces. I have been trying to do isogrids and other grids parametrically in Fusion with no luck. So manual it is. But The base could look like the following. In T1 image the outer parts are 50% the weight of the solid base. The small holed version does better.
In T2 image the longitudinal holes do much better then the thru holes. makes sense as this is like a series of I beams... I did run a generative, but it didn't tell me much. So the long holes can be achieved by using plastic conduit and the base would be two parts held together by the "walls'. No I have to decide on the machine size and do some modelling... It became way too big last time I got into it... Peter
technically you don't really need the bottom part of the bed. you could mount stuff to the side of the top part, the most the bottom part would do is redirect chips/coolant.
Hi Ard - Thats a beast - no saddle, the trunnion is on its own axis. Very nice. Separation of the axes is a good thing. I'm warming to lifting gantries...Peter
Hi All - Sika sell product through my local hardware so I can order the grout and leveller in from them. Very convenient. Now to get a quote from the hardware. Peter
check this one out
Hi Ard - Thanks this robot config is called "Delta" There have been mills built like this but they have not scaled well and are rare. Its a great little animation and I think that will be it, I'd like to see real swarf from such a machine.. Especially with the cobot carriage. Serious machining currently needs serious structures. They also loose accuracy at the edges of their envelope. Deltas are very successful in fast pick and place applications in electronics manufacturing. Peter
the main purpose is probably welding and then machining the weld for a cleaner look, maybe something for aerospace that requires a cleanroom environment that a regular machining center would not be able to provide at this size.
Starrag's ecospeed could be categorized as a delta I think?
Hi Ard - I think that would be classed as a hexapod? Its like a plane simulator. But I can't see 6 arms only 3. maybe a tripod The attached doc discusses some alternative machine types vs cartesian machines. Peter
High Precision Hexapods (newport.com)
Hi Pippin - I thought I published costs here somewhere but can't find them so:
1) Bunnings sikagrout 3350 - one bag minimum order $110 aud plus, from memory was a shock
2) I was in my local hardware so asked, they called sika on the spot and it was $80aud per bag 2 weeks to get it here. So ask your local hardware that sells Sika product
3) HE80AG is about $35 per bag available per 20kg bag at Bluey warehouses E~40GPa
4) Lanko 701 class C grout Bunnings $37 per 20kg its a CSA/portland mix. Made by sika but no published modulus. So I expect around 35GPa... add 3mm blue metal and it will go up. Like HE80AG
5) sikagrout ultra E=33GPa its also self levelling CSA/portland mix
Thats about it I think... Peter