[ishi]

A big machine. We watch with great interest.

Cheers
Roger

Well, you certainly made my day Roger!

Cheers mate.
Ismael

PS: If you know a supplier of high-precision granite down under, I would love to talk to them. I took my kids to Australia for a road trip from Sydney to Melbourne a couple of years ago. On our way there, we stopped at a restaurant where they served us beef sizzling on a hot stone. To this day, they keep talking about it, so I'm constantly looking for an excuse to go back... In any case, one of your banks expressed interest in my software (my day job), so I might be down there in September or October anyway. It would be great to meet you then.

[RCaffin]

My chat was with the owner of Precision Marble, Jersey St, Hornsby, Sydney. Old guy, Italian, the owner, probably trained in Italy. No web site - probably does not need one.

I made off with some broken bits, rejects, as cheap surface plates. He has a huge polishing machine so your tombstone reflection is dead clean (sorry).

Cheers
Roger

[ishi]

It's the end of the week, and it was a productive one, so I'm winding down and reflecting on our little project.

I then ask myself this question: why are we building machine tools?

What is the motivation for this endeavor?

We all have our reasons. For many readers on this forum, it's how they make a living. For many others, it's just a hobby.

For me, the reasons are more indirect and personal. Deep within, they come from what my grandfather used to tell me, all the time: "a good worker has good tools". He was a farmer, but he had a love for mechanics. As a teenager, he wanted to be a motorcycle repairman. But his father, a farmer himself, would have none of it. One day, my grandfather came back home with a brand new motorcycle that he had bought with his hard-earned savings. His father thought otherwise and ordered him to return the bike. So he did, heartbroken. Growing up, he developed a very successful farm, but deep in his heart, he always had a desire to dabble with mechanics. Unfortunately, he did not receive any formal training and could only build very basic machines and tools.

I am a software engineer by training and by trade, but I have always wanted to get my hands dirty. During my first year of engineering school, I spent six weeks working as a coal miner in the deepest mine in Europe (-1,800m). These were the best six weeks of my life! And ever since, I have always wanted to build machines and tools. Tools that my grandfather would have liked to use to build and fix motorcycles. Today, I have the opportunity of doing just that. My grandfather passed away a long time ago. Before his passing, I bought him a Harley-Davidson leather cap. He wore it all the time with a huge smile on his face. If I I succeed in building a solid machine, I like to believe that he would have enjoyed working on it, building some cool motorcycles.

How about you? Why do you build machine tools?

[ishi]

My chat was with the owner of Precision Marble, Jersey St, Hornsby, Sydney. Old guy, Italian, the owner, probably trained in Italy. No web site - probably does not need one.

I made off with some broken bits, rejects, as cheap surface plates. He has a huge polishing machine so your tombstone reflection is dead clean (sorry).

Cheers
Roger

I'll pay him a visit then! Thanks a lot for the tip Roger.

[RCaffin]

Why do you build machine tools?
It's never that simple.
I wanted to make some very specialised ultra-light mountaineering gear to serve a very niche market, and a friend pointed out that I could buy a small CNC machine for what I would be paying an outside firm for the N generations of prototypes. (N was not small.) So I did - a very solid and well-made mill.

But the original electronics were based on S100 in W95 (or was it DOS?), and had to be replaced. Unfortunately, the local firm which did the replacement was not up to it and parts started to die. It became unsupportable.

So I stripped ALL the electronics out and rebuilt it. This was not difficult for me as I am a retired research scientist, with expertise in robotics, electronics, computing, ... physics and measurement. It would be fair to say that I got sucked in! These days I machine hardwood, plastics, aluminium, steel, titanium, quartz, basalt and granite. (The last 3 under water.)

Cheers
Roger

[ishi]

Why do you build machine tools?
It's never that simple.
I wanted to make some very specialised ultra-light mountaineering gear to serve a very niche market, and a friend pointed out that I could buy a small CNC machine for what I would be paying an outside firm for the N generations of prototypes. (N was not small.) So I did - a very solid and well-made mill.

But the original electronics were based on S100 in W95 (or was it DOS?), and had to be replaced. Unfortunately, the local firm which did the replacement was not up to it and parts started to die. It became unsupportable.

So I stripped ALL the electronics out and rebuilt it. This was not difficult for me as I am a retired research scientist, with expertise in robotics, electronics, computing, ... physics and measurement. It would be fair to say that I got sucked in! These days I machine hardwood, plastics, aluminium, steel, titanium, quartz, basalt and granite. (The last 3 under water.)

Cheers
Roger

I love it!

A friend of mine cuts carbon fiber underwater:

https://www.youtube.com/channel/UCJ4...5FOHg/featured

I would love to cut carbon fiber and granite underwater! I just don't know what that means for the motors, roller guides, and ball screws. How do you protect them from the water?

[RCaffin]

what that means for the motors, roller guides, and ball screws.
Rust, more rust, and yet more rust, IF they get wet.

I use a 'water bath' with very high sides. Water pours in over the cutter and drains out the bottom. If I get it right than there is no water anywhere near the table or the rails. There were a few hiccups at the start, quickly fixed.

I did expect a huge amount of spray from the spinning cutter. In fact, while there was of course some spray out sideways if the cutter was exposed, it was not that bad, and it did not fly UP in the air. So high side-walls on the bath were enough. If the cutter is submerged, there may be no spray.
Attachment 397190
Here the cutter is not 'exposed' so there is no spray. I was drilling 1 mm holes in ruby balls to make touch probe stylii. Buying drilled balls was very $$$. The tricky bit is that the ball mount has to be spring-loaded with no wobble, so the 1 mm diamond drill does not wander and is not scrunched. Drilling ruby is slow. The white ring you can see in the water is ruby dust!
Attachment 397192
Here the cutter is exposed, but I have high sidewalls, some of them clear so I can see what the machine is doing. This is basalt. The hardest bit is sealing off the shaft from the rotary table and counter-headstock: baffles and slingers work. The basalt dust collects at the bottom: a real sludge.

Cheers
Roger

[ishi]

what that means for the motors, roller guides, and ball screws.
Rust, more rust, and yet more rust, IF they get wet.

I use a 'water bath' with very high sides. Water pours in over the cutter and drains out the bottom. If I get it right than there is no water anywhere near the table or the rails. There were a few hiccups at the start, quickly fixed.

I did expect a huge amount of spray from the spinning cutter. In fact, while there was of course some spray out sideways if the cutter was exposed, it was not that bad, and it did not fly UP in the air. So high side-walls on the bath were enough. If the cutter is submerged, there may be no spray.
Attachment 397190
Here the cutter is not 'exposed' so there is no spray. I was drilling 1 mm holes in ruby balls to make touch probe stylii. Buying drilled balls was very $$$. The tricky bit is that the ball mount has to be spring-loaded with no wobble, so the 1 mm diamond drill does not wander and is not scrunched. Drilling ruby is slow. The white ring you can see in the water is ruby dust!
Attachment 397192
Here the cutter is exposed, but I have high sidewalls, some of them clear so I can see what the machine is doing. This is basalt. The hardest bit is sealing off the shaft from the rotary table and counter-headstock: baffles and slingers work. The basalt dust collects at the bottom: a real sludge.

Cheers
Roger

Man, this is really cool! So, in essence, it's localized water-based containment. That makes sense. We could do that with our setup. I love it!

If you allow me, I'll definitely stop by your place next time I'm down under.

Cheers!

Ismael

[handlewanker]

Hi, I'm amazed you now consider it a good idea sending components out from the suppliers directly to the customer for assembly...…..that would worry me mainly from a QC aspect, as you wouldn't know if the customer stuffed up the build.....by mishandling..... or received wonky parts......that's just my opinion, but I've always worked on the idea that if you want it right you have to be there when it hits the road...….etc.

I could not imagine the backlash and bad publicity you would get …...from the education community as a whole......if they started experiencing problems with alignment and/or setting up after having spent $150K+ assembly time...whatever.

I think it would be advisable to have a select small team of techs to assemble the machines on site and to commission them......anything that goes wrong after that is purely your worry from a QC point of view...…..internationally that could be a challenge.

No doubt the Chinese would seize on this aspect and would supply a completely turnkey machine ready to go from the box......mine did, and I only bought a bespoke 3(4) axis CNC mill for hobby use.

OK, so I'm being super negative...….once the prototype is finished it will be as good as you make it...…...that is after hours of set and reset to get it to function reliably……….the production model assembly cannot be based on a prototype unless it is exactly the same as the prototype.....ask any car maker.

BTW, imagine assembling a current model car from a box of bits and pieces because that is how the manufacturers want to do it.
Ian.

[Goemon]

I love it!

A friend of mine cuts carbon fiber underwater:

https://www.youtube.com/channel/UCJ4...5FOHg/featured

I would love to cut carbon fiber and granite underwater! I just don't know what that means for the motors, roller guides, and ball screws. How do you protect them from the water?

Way covers and a flood coolant table would work.

Cutting carbon fiber under water is a good idea because the dry dust when you cut it is very dangerous. Most of the people I know who cut carbon fiber invest in a high qualiy forced air full head protective mask but that wouldn't be comfortable over a long job. I spray water over CF parts before cutting to stop the CF getting into the air. It's almost as bad a second asbestos.

[ishi]

Hi, I'm amazed you now consider it a good idea sending components out from the suppliers directly to the customer for assembly...…..that would worry me mainly from a QC aspect, as you wouldn't know if the customer stuffed up the build.....by mishandling..... or received wonky parts......that's just my opinion, but I've always worked on the idea that if you want it right you have to be there when it hits the road...….etc.

I could not imagine the backlash and bad publicity you would get …...from the education community as a whole......if they started experiencing problems with alignment and/or setting up after having spent $150K+ assembly time...whatever.

I think it would be advisable to have a select small team of techs to assemble the machines on site and to commission them......anything that goes wrong after that is purely your worry from a QC point of view...…..internationally that could be a challenge.

No doubt the Chinese would seize on this aspect and would supply a completely turnkey machine ready to go from the box......mine did, and I only bought a bespoke 3(4) axis CNC mill for hobby use.

OK, so I'm being super negative...….once the prototype is finished it will be as good as you make it...…...that is after hours of set and reset to get it to function reliably……….the production model assembly cannot be based on a prototype unless it is exactly the same as the prototype.....ask any car maker.

BTW, imagine assembling a current model car from a box of bits and pieces because that is how the manufacturers want to do it.
Ian.

Ian,

It would make no sense to ship a granite base and column to a warehouse, then ship it again to the customer. Direct shipping for this type of component is much more efficient from a supply chain standpoint. As far as quality control is concerned, I don't see how we could avoid sending a qualified technician on site in order to inspect all the components once they've been received, and get them signed off by the customer before assembly. After that, the customer could do the entire build on their own, or pay us to help them with the build. But ultimately, they are responsible for the build, much like when someone builds a kit plane.

Anyone is free to copy the design and sell it any way they want. This is the whole point of releasing the design in the Public Domain. I am not trying to avoid that. Instead, I am trying to encourage it, because it fosters innovation in such a way that everyone can benefit from it. Think of it as Open Source for hardware. It did wonders for software like Linux or Electronics like Arduino. I see no reason why the same could not be done for machine tools.

[Goemon]

$150,000 for a kit sounds high.

You can buy a ready to use similar size Datron CNC mill for than money and they are precision high speed machining centers (with granite tables).

You can get a lot more for that kind of money from Haas too. Why would an educational institution spend that kind of cash on a kit from an unknown new manufacturer over a ready run fully supported machine from an established brand?

I think there are a few reasons people choose the DIY route. Mostly it is due to budget limitations or the requirement for something custom that I should not available off-the-shelf. For hobby users, it can be a fun project and a learning experience but not for $150k.... or even $100,000 or $50,000. People expect plug in and play at that level.

[Goemon]

Why would granite be easier to design or build with than epoxy granite? I would have said the opposite.

I just built a CNC machine base and gantry using epoxy granite with a granite surface plate. Epoxy granite is considerably easier to work with than granite. It can be easily cast into one-piece machine bases. You can cast E.G parts with all the t-slots and threaded inserts you need, no further milling and drilling is needed. E.G. Is easy to cast flat and hand scrape the edges for extra precision. Real granite is too hard for most tools. Real granite is also expensive, easy to crack by accident and very difficult to repair.

Epoxy granite also has superior vibration damping properties and, it can be easily combined with other materials to create strong and stiff design structures. For example, my gantry is a mix of carbon fiber and epoxy granite cast around a steel skeleton with embedded hardened tool steel bars (to hold screw threads for my actuators). I get the benefits of all of these materials with this composite design. I.e. It's incredibly strong and stiff with great vibration damping and an incredibly hard mounting surface for my rails. It's a lot harder for combine materials with solid granite slabs....

I used a real granite surface plate under my Y-axis to save time but, if I had plans to sell kits, I think using real granite would end up causing a bottleneck.

[ishi]

$150,000 for a kit sounds high.

You can buy a ready to use similar size Datron CNC mill for than money and they are precision high speed machining centers (with granite tables).

You can get a lot more for that kind of money from Haas too. Why would an educational institution spend that kind of cash on a kit from an unknown new manufacturer over a ready run fully supported machine from an established brand?

I think there are a few reasons people choose the DIY route. Mostly it is due to budget limitations or the requirement for something custom that I should not available off-the-shelf. For hobby users, it can be a fun project and a learning experience but not for $150k.... or even $100,000 or $50,000. People expect plug in and play at that level.

Goemon,

I think we are comparing apples and oranges here. As far as I can tell, neither Datron nor Haas sell a true 6-axis machine. Furthermore, the Datron machines are vertical, not horizontal. And the Haas machines do not have absolute encoders on their linear axes, unless you add them as an option, which starts at a whopping $15,895. You also do not get a high-speed spindle on a Haas, unless you go for the CM-1, but in that case you get a cutting envelope that is 8 times smaller, and your spindle is 3 times less powerful. And most of the rotary axes on these machines use regular servo motors, not torque motors. I would also contend that the SINUMERIK platform is a lot more powerful than the Haas platform.

The following spreadsheet outlines our design and components in details:

https://docs.google.com/spreadsheets...gid=1109769669

If you spend the time to review it carefully, you will see that very few machines are built with this type of components in that price range. In fact, as far as I can tell, there is none. For example, once you load the Haas CM-1 with all the options that would bring it closer to what we are building, retail price reaches $113,915, and you still have an envelope that is 8 times smaller, and you still do not have linear encoders. And did I mention that your piece cannot weigh more than 1.4kg once you put it on the TRT70 2-axis rotary table? I have yet to do all the maths, but it's quite likely that our rotary table will support pieces with weights in excess of 250kg...

Regarding the fact that we are planning to sell a kit, I totally agree that it will reduce the addressable market, but this is just a way to get started. If the machine works, nothing would prevent us from selling fully assembled machines if there is a market for it. And I am convinced that there is a market once people understand the benefits of a true 6-axis machine.

Regarding the focus on the education market, it's just a way to get started as well, because it will be very difficult to convince a commercial shop to make a gamble on an unproven company with an unproven design. But a school will look at this type of risk under a very different light. For progressive-thinking schools, the availability of the machine as a kit is actually a plus, because they can use it as a training opportunity. And the release of the machine's design into the Public Domain is a huge benefit, because it will allow their students to extend the machine. This is how Open Source software works, and this is why it is prevalent in academia. I do not see any reason why something similar could not be done with hardware, and it's already happening for electronics with platforms like Arduino.

Finally, as mentioned in earlier posts, I believe that an entry-level version of the kit can be sold for $80k to $90k once you get some volume (10 or 20 units) and you switch to more affordable components (NUM instead of Siemens, Fagor instead of Heidenhain, HIWIN instead of NSK). But from an engineering standpoint, it will be a lot easier to go downscale rather than upscale, because a machine's accuracy is only as good as its weakest component, and when you start from the bottom, you have no way of knowing which one that is.

[ishi]

Why would granite be easier to design or build with than epoxy granite? I would have said the opposite.

I just built a CNC machine base and gantry using epoxy granite with a granite surface plate. Epoxy granite is considerably easier to work with than granite. It can be easily cast into one-piece machine bases. You can cast E.G parts with all the t-slots and threaded inserts you need, no further milling and drilling is needed. E.G. Is easy to cast flat and hand scrape the edges for extra precision. Real granite is too hard for most tools. Real granite is also expensive, easy to crack by accident and very difficult to repair.

Epoxy granite also has superior vibration damping properties and, it can be easily combined with other materials to create strong and stiff design structures. For example, my gantry is a mix of carbon fiber and epoxy granite cast around a steel skeleton with embedded hardened tool steel bars (to hold screw threads for my actuators). I get the benefits of all of these materials with this composite design. I.e. It's incredibly strong and stiff with great vibration damping and an incredibly hard mounting surface for my rails. It's a lot harder for combine materials with solid granite slabs....

I used a real granite surface plate under my Y-axis to save time but, if I had plans to sell kits, I think using real granite would end up causing a bottleneck.

Goemon,

I totally agree with you. Granite was just simpler for me to design for. Simple shapes, no internal frame, etc. This is why we started with this material initially. Now that our project has evolved the way it has though, we are seriously considering switching to epoxy granite. It would be a lot more design work and the selection of the supplier would be more challenging, but the benefits are clear, exactly as you outlined them: much better vibration damping, higher robustness, easier mounting of rails, etc.

In order to facilitate our investigations, can you point me to some literature on the subject? Also, can you recommend any supplier?

Many thanks in advance for your help.

Ismael

[ishi]

The whole day was spent flipping models around in order to figure out how to mount the two servo motors used to drive the Z axis. Eventually, an acceptable solution emerged: the motor brackets should be attached vertically to the X-axis carriage, instead of horizontally as envisioned originally. This change allowed us to get rid of the "feet" for the X-axis carriage, thereby making it quite a bit lighter, and much more rigid. The only drawback of this design is that motors are now protruding in front of the machine's base, which might need to be extended by 5". If we do so, we will widen the machine by 5" as well, giving it a floor footprint of 69" x 69", thereby exactly matching the one of the DATRON M8Cube. In the meantime, I still need to work on the custom ball screw nut mounting brackets that will attach the Z-axis carriage to the nuts.

***

High-res pictures available on the project's drive:

https://drive.google.com/drive/u/3/f...3dQrx?ogsrc=32

[ishi]

Here is a first version of the brackets that could be used to attach the Z-axis carriage to the ball screw nuts. They could be milled from either aluminum or steel (preferable). The goal was to make them as rigid as possible, because there is a full 131mm between the bottom of the Z-axis carriage and the ball screw axes. The machine's footprint is now 1,750mm x 1,750mm. Most importantly, travel on X can now be extended from 30" to 40" quite easily. This is due to the fact that the base is 5" wider and that we have saved a bit more than 5" by removing the feet from the X-axis carriage. Of course, taking full advantage of this longer travel would require that we extend the length of our T-Slots table and underlying Z-axis carriage, but this should not be too much of a problem. We'll keep that for later though.

***

High-res pictures available on the project's drive:

https://drive.google.com/drive/u/3/f...3dQrx?ogsrc=32

[RCaffin]

You do know that the single bearings at the far end of the ball screws must be a floating fit? Just checking.

Cheers
Roger

[ishi]

You do know that the single bearings at the far end of the ball screws must be a floating fit? Just checking.

Cheers
Roger

Yes, of course, but thanks for checking anyway. Better safe than sorry. Fixed on the motor side (BK), floating on the other end (BF).

I'm also missing the shaft couplers in the 3D model, but these will be added later on.

Just trying to make sure that everything can fit together.

It's a really interesting puzzle... So many constraints that you have to deal with. Once you really get into it, you quickly realize that there are not very many solutions to the problem. That's why most machines end up looking very similar to one another. Once you settle on a given configuration, everything flows from there, but finding the path of least resistance is anything but easy...

[handlewanker]

In the real World, everything is built down to a price...…..if you want to get more profit from the build you go offshore to the cheapest supplier and cross your fingers for the quality and longevity of the cheaper inventory you are now offering.....ask me how I know that to be true..

Usually, and more often than not, anyone who wants better performance strips out the cheap stuff and loads it up with top of the class goodies...….custom cars are in this category.

You would not find anyone buying a from the ground up custom car for a performance agenda unless it was a strictly race track performer and made to order.

As this endeavour is to specifically train people in the 6 axis mode, quality of the output is not a real issue as the end products are not a production item that had to be assembled to give you a marketable product...…..that is, the test pieces get binned when the class goes home or used as trophies.

I would think that once you had mastered the HMC 6 axis mode of working...….(I like this description of this type of machine better than the omnio thing)…. doing it for real on a better high class machine would be something you got paid for and did in another environment that had high class machinery for their production, something that in a class room is not really needed as part of the deal.

This would dramatically cut the cost of the outlay down …..these training machines could/would experience many crashes and so would not have a very high resale value.

I suppose if you wanted to sell such a machine on you could patch up an EG built machine if it showed wear and tear, so high class components are not really a benefit for the initial purchaser.....a 5 year life span would be a good expectation as technology races along.
Ian.