[mactec54]

Finally making some progress. Main steelwork finished and painted. Hopefully will get this installed this week, then can start on setting up the slides and drives.

All taking longer than planned, but I suppose anyone who has built a machine before knew that already

Projects like this take some time, more so when it is a custom build like this, looks good though

Where you able to machine the top Beams on these portals for the Rails Etc to mount

Did the filling of the Beams work as expected, and what mix did you use

[jono5axe]

Projects like this take some time, more so when it is a custom build like this, looks good though

Thanks, it is good when there is finally something to see for the work.

Where you able to machine the top Beams on these portals for the Rails Etc to mount

At that stage now, will make some decisions this week.

Did the filling of the Beams work as expected, and what mix did you use

Yes, it worked out pretty much as planned.
- the cross section of the steel RHS is now stabilised.
- the internal components are all fixed in place by the epoxy mix.
- vibration dampening seems very effective from what I can determine at this stage. If I knock the beams with a wooden mallet it makes a very muted dull thud, whereas if I knock an unfilled large RHS section with the mallet it rings like a church bell in an echo chamber.

But, something to consider, the epoxy concrete part of it was quite a lot of work and time consuming (but I suppose everything has been quite a lot of work, everything has more detail that consumes more time than I had planned).

Mix used was:
- aggregate = 1/3:1/3:1/3 of sand, 7mm & 13mm (by volume)
- plus resin at 8% of aggregate by weight.

Each main beam has approx 300kg of epoxy concrete in it. Hopefully we will see some benefit from it when trying to cut good surface finishes on 3D shapes in duratec'ed and/or aluminium patterns.

[mactec54]

Thanks, it is good when there is finally something to see for the work.



At that stage now, will make some decisions this week.



Yes, it worked out pretty much as planned.
- the cross section of the steel RHS is now stabilised.
- the internal components are all fixed in place by the epoxy mix.
- vibration dampening seems very effective from what I can determine at this stage. If I knock the beams with a wooden mallet it makes a very muted dull thud, whereas if I knock an unfilled large RHS section with the mallet it rings like a church bell in an echo chamber.

But, something to consider, the epoxy concrete part of it was quite a lot of work and time consuming (but I suppose everything has been quite a lot of work, everything has more detail that consumes more time than I had planned).

Mix used was:
- aggregate = 1/3:1/3:1/3 of sand, 7mm & 13mm (by volume)
- plus resin at 8% of aggregate by weight.

Each main beam has approx 300kg of epoxy concrete in it. Hopefully we will see some benefit from it when trying to cut good surface finishes on 3D shapes in duratec'ed and/or aluminium patterns.

The Beams should machine where needed very well also

[jono5axe]

What flatness values are you measuring with that method awerby?

[koss2j]

Just keeps getting better Jono! This is going to be a monster! Really looking forward to it cutting some material!

[matth]

Gauge plate steel or tooling plate / mic6 aluminium.

[matth]

Very interesting. Good luck with it.

[koss2j]

Looks great Jono! Please keep the updates coming as I too will be building a 5 axis though not quite as huge as this monster!

[Zorbit]

Excellent thread, I'm enjoying it.

Have you considered a nutating head ? I have one on a 5 axis Morbidelli ( also HSK63F ), it's rigid and compact.

[jono5axe]

Hi there. Is that an available package? If so, where from? What is that spindle? What is the Z travel on that machine? I had only seen flat panel Morbidelli machines, but that is obviously something different than a flat panel router.

Yes, I did consider that head format, pros & cons etc. I think recall that the main advantage (45 degrees) was being able to get in a bit tighter on the workpeice in some situations, which increases the machining envelope of a given machine (?). As I am not experienced at motion control I decided to go with (what seemed to me) the simpler 90 degree setup. It also seemed that there was more information out there for me to use if I run into setup/software/programing problems. I will make up some sort of IP67 bracket arm, maybe from composites, or just aluminium profiles. The 90 degree setup is also quite straight forward to locate the servos in the assembly using belt drives onto the harmonic drives.

But please let me know if there is some major advantage with the 45 degree setup. As I say, I had to make a decision from a fairly uninformed start point, so I did a bit of research and came to a (moderately) informed decision.....

I have the spindle, harmonic drives & servos already, based on a 90 degree setup. They were sized on calculation, starting with the torque I wanted in the harmonic drives (torque on the tool tip) and then comparing/checking what the big name machine suppliers use. I think I based my calcs on each axis being able to get through (rapid) 360 degrees in 1.0 second. A lot of the machines that I have seen cutting in simultaneous 5 axis mode seemed to be limited by slow A & C axis movement, and I wanted better than that. But it will only be proved in the pudding, of course.

[shedbob]

Hallo jono
Very interesting and ambitious project here.The scale is impressive.
On epoxy leveling ukcnc seems to be the forum where epoxy leveling is the go to method.Those builds go into considerable detail.
If I recall accurately this build has some good detail as a starting point.

BUILD LOG: A sufficiently strong machine

I wish you good problem solving on this project.
Robert.

[Zorbit]

The machine is an Author X5, mine is about 15 years old but still going well. They call the spindle Prisma, it's 11kw / 15hp, 18000rpm. X axis 3200mm, Y 1300 ish, I can fit 250mm between the guards and pods / rails, but larger work is possible if you get creative with workholding.

The nutating head does allow a good work envelope and is very rigid. The spindle axis is very close to the outside diameter of the spindle, so it's possible to get the tool close to the pods / rails. I machine aluminium and Delrin on it regularly, the finish is almost as good as on the VMC.

[jono5axe]

Hi Zorbit. What CAM do you use for simultaneous 5-axis machining?

[Zorbit]

Hypermill 2018. Expensive, but good. A few years ago I considered building a machine similar to yours, to make moulds for small yachts, and at the time Delcam looked like the best bet.

[jono5axe]

I think that I can officially declare that self leveling epoxy sucks.

Maybe for small areas it is ok, but for longer beds it is just not possible to get it to flow out flat enough. Even when being very exact with putting the right amount in specific zones to ensure that the required flow is minimal and just local leveling is sought, I am still getting poor results. If I am not careful I can get high/low spots of +/-1.0 mm or more (which is I presume the form of a frozen flow wave) but even a good pour is high/low of +/- 0.1 mm or more over 300mm spans. Epoxy is a special low viscosity resin and gel time is two hours so that is all fine. Lots of hand work required (precision hand sanding, staight edge, precision level checking) to get it in any kind of shape. Across the bed is OK (level and flat) but longitudinally is rubbish.

[Note: I am putting a gauged plate on top of the epoxy when flat. This plate follows the faults in the epoxy to a degree, for example +/- 0.05mm over 300mm]

Question:

Regarding flatness of beds for linear rail mounting (medium precision/preload) can anyone please tell me tolerances for flatness. Generally the linear rail manuals do not state tolerances on the bed flatness requirements, just stating "flat and straight mounting surfaces". I have found various info that would suggest max allowable values of 0.02mm out of flat over 500mm (for medium precision/preload rails up to 45mm) but this maybe seems a bit extreme to my thinking. Please if anyone has any knowledge here I would be grateful to hear it.

At the moment it looks like I have a lot of hand scraping ahead of me.

[mactec54]

I think that I can officially declare that self leveling epoxy sucks.

Maybe for small areas it is ok, but for longer beds it is just not possible to get it to flow out flat enough. Even when being very exact with putting the right amount in specific zones to ensure that the required flow is minimal and just local leveling is sought, I am still getting poor results. If I am not careful I can get high/low spots of +/-1.0 mm or more (which is I presume the form of a frozen flow wave) but even a good pour is high/low of +/- 0.1 mm or more over 300mm spans. Epoxy is a special low viscosity resin and gel time is two hours so that is all fine. Lots of hand work required (precision hand sanding, staight edge, precision level checking) to get it in any kind of shape. Across the bed is OK (level and flat) but longitudinally is rubbish.

[Note: I am putting a gauged plate on top of the epoxy when flat. This plate follows the faults in the epoxy to a degree, for example +/- 0.05mm over 300mm]

Question:

Regarding flatness of beds for linear rail mounting (medium precision/preload) can anyone please tell me tolerances for flatness. Generally the linear rail manuals do not state tolerances on the bed flatness requirements, just stating "flat and straight mounting surfaces". I have found various info that would suggest max allowable values of 0.02mm out of flat over 500mm (for medium precision/preload rails up to 45mm) but this maybe seems a bit extreme to my thinking. Please if anyone has any knowledge here I would be grateful to hear it.

At the moment it looks like I have a lot of hand scraping ahead of me.

That's a big number .02 for that type of linear Bearing just figure how much clearance is in the Bearing and that is the max tolerance you can have on the flatness of the mounting surface, A preloaded Linear Bearing you don't have anything to play with for rail flatness tolerance, using epoxy it is not an ideal mounting surface as it will deform when you torque down at each Rail mounting point, any mounting tolerance you had will be lost just with the deforming of the surface

[awerby]

It sounds like your epoxy was too viscous. I'd suggest scraping it off and trying again; this time thin it with some acetone until it levels out immediately.

[Zorbit]

Acetone can also inhibit the cure - so it remains permanently weak. I tried it some years ago to see if I could achieve very deep penetration into wood.

[pippin88]

How thick is your epoxy pour?

I found I needed quite a thick layer. A good 5mm. I remember reading a recommendation for 1/4" (6.35mm) thick layer - can't find the source however.

There is a fair bit of surface tension.

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[pippin88]

The linear rail spec sheets will have specifications for all the allowable tolerances.

What matters is that the two rails are equal. That is why spec sheets don't concentrate on flatness - they talk about parallelism and height tolerance.

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