[Rodm1954]

I started to make a desktop machine from 8020 type section but soon had plates wrapped around all the sections and it sort of got out of control.
The machine is built like a tank and weights more than I care to lift.

From the original concept of a portable desktop this will be permantetly mounted on a trolley. This will give me the chance to make a slide out console and use two 8 inch touchscreens for monitors - only because it looks like a fun way to use them.

I wanted a moving gantry as I am not keen on moving table designs. I have cranked the gantry sides so the cutter is centred on the table and keep the table as short as possible. I am running dual screws on X axis to keep it rigid and hence the name Tubot.

Electronics will be Gecko540, Smoothstepper, DC03 for spindle control and Pokeys for console switches and pots.

Note the X axis rails are up high to reduce the height of the gantry sides. I stitched an 80 by 80 and a 40 by 80 beam together to make the 120 by 80 gantry beam. It is all covered in plates so that adds to the t slot fixings. The t slot table is fixed to 40 by 6 ally angle from underneath and then into the 8020 beam so no fixings are visible in the table. Cutting envelope is 330 by 250 by 110mm.

This is a side project so progress will be as time permits.

[Rodm1954]

All the mechanicals finished today so I will go back to finishing the trolley and console. Travel worked out at 330 by 250 by 115. I have two positions for the spindle to provide a bit more clearance for a 4th axis.

[Jesse B]

That looks fantastic so far, very nicely built.

[Rodm1954]

Thanks Jesse,
It has been a good little project to do.

[Rodm1954]

Working on the trolley the machine will be mounted on and finished the console. The console is on it's own cabinet which slides on six drawer runners into the base of the trolley. Makes it nice and compact for storage and protects the console when not in use. The trolley will have sides installed to cover the drawer runners when closed. A perspex lid will lift upwards to give some protection from dust and swarf while in use.

I have fitted one of those 8 inch high resolution vehicle touchscreens and it display 1024 by 768 good enough for me to see. The mini keyboard and trackball is embedded in to the facia - see the perspex holder in the photo.

The rest is fairly standard console features and function buttons and pots for feed, jog and spindle speed. The console will operate through a Pokeys which I have found to be excellent for both analogue and digital signals.

[Rodm1954]

To update the build I am working on the electrics and electronics.

I have built a panel and mounted a 300mm square switchboard in there for the electronics. The VFD is housed in a galvo box to prevent EMI. The power supplies are mounted on the back of the swichboard which means no high voltage is inside with the electronics. There is a smoothstepper, G540 and CNC4PC C10 BOB and room for more if needed.

The power supplies are 48vdc for driver, 12vdc for 6 air cooling fans and a 5 volt for the signals and electronics. While this may look a little vulnerable the panel is enclosed in the cabinet and you cannot get to the back of the panel unless you remove the console or take the panel.
A further two power packs are mounted on the next shelf for 8 inch monitor and USB hub.
I have used flush mount 3 pin sockets (240 volt) so that any electrical component can be easily disconnected from the machine.

First 3 photos show this better than I can describe it.

The last photo is the bottom shelf which houses an air pump which is again covered with a glavo box to prevent EMI and a Mini ITX computer goes on the left side of the shelf where all junk is at the moment. Monitor, USB, etc route through the back of the console which has been removed while I play with the electrics. If you look at the framework above that shelf you can see the rivnuts where the electrical panel mounts.

I am waiting on new electrical switches from China as the first lot sent were momentary - my fault for being too quick on the buy trigger.

It is raw but in three weeks when I get the new switches I should have it all finished and mounted and hopefully it should present a lot neater.

The last two photos show a mounting bracket for the cable chain on the Z axis. The microphone plug is for a touchplate for Z axis zeroing.

[mmcp42]

very neat build there

one of your pictures seems to show mains IN as a socket - surely my eyes deceive me - that would mean the mains is cmoing in on a lead with pins :nono:

[Rodm1954]

Your eyes are good. I am using the 3 pin socket as a terminal but the power comes into the back of that socket and not through a 3 pin plug in the front. You can see the leads and plug coming in from the side of the two plugs. I want to be able to easily disconnect the main power and all the high voltage connections to lift the panel out of the machine. I could use the front of those plugs as a output and if I do I will re-label it. I hope I have described it clear enough.

[mmcp42]

Your eyes are good. I am using the 3 pin socket as a terminal but the power comes into the back of that socket and not through a 3 pin plug in the front. You can see the leads and plug coming in from the side of the two plugs. I want to be able to easily disconnect the main power and all the high voltage connections to lift the panel out of the machine. I could use the front of those plugs as a output and if I do I will re-label it. I hope I have described it clear enough.

aha I like that a lot better! :cheers:

[Rodm1954]

I had hoped to have it running this weekend but got caught with paint drying so it will be a bit longer.

To update all the electrics and electronics is done except for making the touchplate. Console is back in the machine and once the paint dries on a couple of cable covers it will be complete. The motors lock up as they should, the spindle operates through the console and all else looks good in Mach3. It takes a lot of willpower not to run the machine as it is ready to run but I know once it is running the other bits that need to be done get overlooked.

A couple of photos to show progress since last post. Next post should be a video of it doing its maiden run.

I have a smoothstepper running a Gecko540 and CNC4PC C10 Bob. The 540 does the spindle speed control while the C10 turns the spindle off/on through a Solid State Relay. The C10 has been jumpered for inputs on 2 to 9 so plenty of inputs and outputs with the 540 and C10. Around the spindle is a laser crosshair operated through the C10 and an aquarium electromagetic air pump is used to pump air through the flexible nozzle on the right. I use these air pumps on all my machines as they provide enough pressure to cool the cutter as well as blow the dust/swarf away without making fine dust like MDF airbourne. They are also quiet when running and you don't jump like when an air compressor cuts in.

[svanommen]

VERY Impressive! I can't wait to see this machine run. Your care for detail is simply impressive. Something tells me this isn't your first CNC build?

Cheers,
Seth

[Rodm1954]

Thanks Seth
Yes I have built a few and keep learning on each new build.

[Rodm1954]

The machine is finally finished and working.

Some pictures of it before it gets too dusty.

You can probably see better in these photos how the base expands with the console sliding out and I have made a perspex cover which doubles up as a shield when the machine is in use.

A mini ITX computer lives in the base of the machine and is turned on through the console. I had to use a cable chain to carry the wires to the console as they were getting pinched when the console was pushed in.

[CNC Lurker]

Wow, you paid a lot of attention to detail, great job!:cheers:

[Rodm1954]

Thanks CNC Lurker

I had better explain why I have put this in the design thread rather than a build thread. I wanted a rigid machine that would occupy a small footprint in an already over crowded shed. I think I have achieved that without compromising any features.

The console is a major achievement as can be seen it slides into the base when not in use. The perspex cover serves as a guard when it is in user mode. The console has all the major user interfaces so there is little need to use the touchscreen or mouse to operate the machine.

The machine has dual ballscrews on X axis hense the name Tubot or Two Bot. This provides a rigid X axis without racking and the advantage of a smaller footprint over the moving table design. Added to this the crank in the gantry sides removes the dead area at the back and front of the X axis travel thereby reducing the table and machine size.

The X axis rails are set high and very close to the Y axis on the machine. This adds rigidity to the machine having shorter gantry sides. The added bonus of this design is a gutter down the table sides to contain the dust / swarf from spraying over the rails and ballscrews.

I have probably gone a bit overboard on the machine structure by plating all the 8020 type material but I am sure it adds to the overall rigidity and mass of the machine. Tapping the table with my fist I get a dull thud so applying backyard engineering I reckon it is about right.

When I run a demo job I'll post a video to finish this thread off.

[Rodm1954]

And the video of it running ...............

[svanommen]

Once again that is one polished machine! Excellent speed. Great cabinet design and layout as well.

Judging by your other machines, I guess you are a fan of the Chinese spindle motors? Any suggestions on the best place to buy from? Looks like you went with a fan cooled version. Do you prefer those over the water cooled ones? My next and (hopefully) last large purchase to complete my bot is a spindle. Trying to decide the best option.

:cheers:
Seth

[Rodm1954]

Hi Seth,
I like the spindles as they are a lot quieter than a brushed motor and you can control them through a console.

The air cooled never seem to get hot so apart from the water cooled being totally sealed I can't see any point in going down that path. Air cooled are simpler to fit without having to plumb the coolant.

I buy from Lovehappy off ebay but would buy from another seller if they were cheaper.

[magma-joe]

Rodm1954,

Very nice work. I like the high x and dual motors to add rigidity to the machine. I am sure you have many many hours in the design and build. I am currently in the design process of a CNC router. Your machine is great food for thought. Do you plan to cut any aluminum with the Tubot?

Magma-joe

[Rodm1954]

Thanks Magma-joe,

I am not good at 3D CAD so my deisgns are in the head and the odd scratch mark on a bit of paper.

I have built quite a few machines and learn from each build. I tend to over build so the machines are strong at least. I wouldn't have any problem with machining aluminum on this machine and expect good results due to the rigidity. I have a CNC mill that I normally use for ally but soon I have to cut some 16mm plate and will see if Tubot is up to it.

Good luck with your build.