[hanermo]

Guys ...
good wood structures, solid, laminated beams, are about 1.5-2x as strong as steel in both stiffness and strength.
By mass.
Sitka spruce is one option.

They need the high H measure for the stiffness, but mass little.

Likewise, optical tables in steel are very much stiffer / stronger than machine tool gantries.
They are very much air by volume.

Aerogels are much stronger than anything else, by mass.
Lab stuff, google it.

At some point suppliers will start to offer std beams in things like aerogel/complex web/optical table cylinder formulations for not much money.
Aircraft, trains, bridges, anything of high value and volume cost about 6$/kg.
(Sales price is different.).

[peteeng]

Hi Hanermo - Thanks for the thoughts, a few decades ago I used airogels for super thin insulation on superyachts in their fridges and hot spots. But I think fullerenes & graphene will be better for machines. Peter

[hanermo]

Anything and everything will be better over time ..
todays vmcs are essentially stressed thin-skin structures of cast iron.

I know of nothing regarding advanced materials in the near future.
In the medium future things like foamed steel might become commodities.

Fullerenes might become available, as filling or as structural.
So might graphene.
It´s driven mostly by money.
Like lion batteries.

Where there is enough money and demand, endless clever engineers who get 2M$/yr will race to improve it, and some will succeed.

Hi Hanermo - Thanks for the thoughts, a few decades ago I used airogels for super thin insulation on superyachts in their fridges and hot spots. But I think fullerenes & graphene will be better for machines. Peter

[peteeng]

Hi All - This morning I pulled down the Z axis and drilled it to suit the spindle plate. I sanded the plate and painted it with matt clearcoat so it had a good hand. All going well. Now to drill the holes in the spindle clamp and that's all done. Next is also to check out the new controller... Peter

[peteeng]

Good day All & Sundry - This morning I gave Frankie a stern lecture on interaxial cancer due to smoking so he gave it up! Yeh! Now the motors turn I can finish assembly in peace. Peter

https://www.facebook.com/ScootCNC/vi...70484449175148

[peteeng]

Evening all - Today I started second fit. Worked thru the bearings and rails, drive nuts. Check all the screws are snug and if so set them with tightbond. The X&Y move well under hand loads over their entire run. One side was a bit stiff and I flipped the drive nut upside down and that fixed that. I mounted the gantry support bearing and snugged that all down. Tomorrow I rebuild the Z axis and get it mounted. Then final checks and install couplings and its TAG> Looks like sawdust this week! Peter

I do need a little 3D printer to make electrical enclosures and clips and small covers better get onto that... I just saw something in one of the photos. Bugger, I have to take the saddle off to get some bolts in.... Hmmm they could be slots next time so a bolt can be slipped up there? I'll think about that...

[peteeng]

Morning all and greasy - This morning I worked thru the XY drive systems and torqued everything down plus set them with loctite on metal or titebond into timber. The squareness is good and the screws backdrive easily by hand. Now to assemble the Z axis and were very close... Peter

I'm thinking next router is lightweight concrete and the mill is full bottle CSA.

https://youtu.be/qlj41jGXuHk My casts will be a bit smoother than this but its a nice muse.

[rodw]

Pete, Here is some local inspiration for you.The bed is about 1200 x 1200mm.
I've been helping Matt with the electronics of this one and he finally had the spindle turning over the weekend!
It runs Linuxcnc with ethercat drives and 12 Nm closed loop steppers. The base plates and rail mounts were machined after casting..
We still have to get the VFD/spindle under Modbus control. Unfortunately, despite the Chinese listing saying otherwise, his I/O board does not have PWM or an encoder input. So controlling the spindle via the VFD is a good way forward. Ethercat makes for a very clean fast build with minimal wiring. I'm keen to build a machine with 240v AC ethercat servos with absolute encoders so homing will be instant and there will be no wiring to speak of.


Matt moved to Linuxcnc from Mach4 as Ethercat was a $1400 option and its free with Linuxcnc. I'm very keen to see the 5 axis mill he has designed come to life!

[peteeng]

Thanks Rod - excellent cast. He didn't cast a gantry! Please keep us informed. 5 axis is next on my list or an industrial robot style machine 7 axis. If Irb then cast concrete parts are the go as well. I'm waiting for some info from Sika AU about their high modulus grout... Peter

1220x1220 same size as Frankie but alot more mass! What concrete was used? Is the gantry 200x200x6mm ?

[rodw]

Pete, I'm not sure on the Concrete specs. That pic was taken over 12 months ago just before got an overseas posting with his employer. Now he's back and working out of Canberra so the machine has left Brissy. I do remember he made a mistake by embedding aluminium into the casting for mounting hardware and the metal coroded quite badly. So stick to steel! I think it was 200 x200 x 6. Once again the rail mounting areas were machined. If it was welded (can't remember), he would have normalised it first.

Here is a recent render of his 5 axis machine. Looks small but the working envelope is a good size



Recently Linuxcnc has some very good kinematics modules developed for 5 axis. I think there may even be one for a multiaxis robot arm too. The 5 axis ones are in a format called switch kins which allows you to switch between conventional 5 axis milling and TCP (Tool centre point) modes. The simulations with models are now included. Here is a quick video I did of one.
https://youtu.be/De5uZbKe8wI

Of course if you want to make a robot, you'll need something like this which fell into my lap last week. A 153:1 precision 1 arc/min gearbox.

This is a planetary design and is missing an input shaft which is straight forward enough to make but it also seems to be missing the sun gear which would be designed to press onto a spline on the input shaft. I will take it to my gear manufcturer and see what can be done. I was told it is worth about $7k.

[rodw]

Pete I forgot to mention I wondered if one of the Lanko floor levellers might suit in lieu of concrete as its fast curing and they make some for industrial floors.
You can get it at Bunnings. I did a floor years ago and it just self levels perfectly. When I went to refresh my memory I found it had been bought out by Sika so maybe thats where the caulking comes from...

[peteeng]

Hi Rod - The level surfaces will use a self leveler. Lanko and Sika have suitable levellers unless its a closed mould. Say 3-5mm thick. But they say 1mm is OK....Nice work with the 5 axis machine, Sounds like portland cement as it has chorides in it that love to eat aluminium. Engineering grouts are choride free. Embedded parts need to be steel as the COE is same as concrete about 13 million bits per degree temp....

IrB Fusion 360 has std robot post processors in their CAM section. Plus 4&5 axis posts. Just got an email back from Sika that the High mod grout is available in NSW, waiting for distributor details. The robot I'm imagining uses ballscrews for motion not gearboxes. This allows it to be stiffer. Theres a large Kawasaki robot (1500kg payload) I like that uses screws vs gears that can drill titanium parts.... but it uses a custom post. Jump that when I get there...





Peter

[rodw]

Whichever way you do it, a robot is not trivial. A lot more than a post processor is required. The machine still needs a way to command the joints in a coordinated way based on a kinematics model.
When the time comes, before you also familiarise yourself with ROS https://index.ros.org/ This is used by Tormach's robot.

[peteeng]

Hi Rod - Yes "not trivial" is correct. The ROS project is gaining momentum. The kinematics is just geometry (esay to say) but I have two companies that are happy to write the kinematics/post if I use their software. But really thought bubbles at the moment. I have two other companies that want painting robots and that could be a good commercial proposition... but dev projects take a long time... Peter

Todays job on Frankie was to correct the spindle plate and z axis bolt holes. The way I marked them out originally put the nuts just under the cars. There is a nub under there that catches, damn. So I moved the holes remodeled the pocket and got that done. I didn't drill the holes as I'm tending to burn the drills at the moment. I have bought a small power drill to mount on Scoot for drilling vs using the spindle. So I spotted the holes and will manually drill them. By tomorrow afternoon Frankenrouter will need that bolt of lightning!! Peter

https://www.facebook.com/ScootCNC/vi...6821762533410/

[peteeng]

Evening all you lot - Today I fitted the spindle plate and spindle clamp. All went well. Now the plate nuts clear the cars and all is snug. Now to second fit the Z axis and mount it. Tomorrow evening sawdust! Peter

[peteeng]

Hi all - I've been looking for an optical centre finder anyone know about these things? Or a laser I can put into the collet? Thanks Peter

[pippin88]

The usual way is to mount a laser or camera offset from the spindle. You align to the align / camera and then knowing the offset you can thus zero the true spindle centre (either with a script in your controller, or using the values manually).

[peteeng]

Hi Pippin - I have been looking for a suitable laser with no luck. I bought a small camera from Jaycar and its hopeless. So any sources are appreciated. Peter

[mactec54]

Hi all - I've been looking for an optical centre finder anyone know about these things? Or a laser I can put into the collet? Thanks Peter

These lasers are quite good.
https://lasercenteredgefinder.com/

[peteeng]

Hi Mactec - Looks great but a little pricy for my level of work. Peter