Sturdy and Fast all Steel CNC , my first build

[GEOFFREY]

Very neat. Keep the piccies coming. G.

[cncJim]

Good job! Thanks for taking photos, sometimes I find it hard to visualise what people have done. The epoxy looks very neat, I would love to see some pictures of it when it's cured. How do you pour it? Just on one side and let it flow down the channel to the other, or fill both sides at the same time?

Did you weld the frame yourself? Looks very good.

Jim

[Boyan Silyavski]

Thanks!

I filled both sides at the same time. The magnets at the corners helped as they were 4.25mm thick, as i could clearly see how much i should pour to achieve 5mm thickness.
As the channels that connect the sides were very thin and i have not mixed enough epoxy, had to mix second time and pour in the channels.

if i was to turn back time, i would have used the same aluminum angle profiles, fix them with scotch only from outside and use cheap epoxy with a brush to make a kind of base, which would close the distance from the channel to the profile against spill. When dry and so secured, pour over the expensive epoxy :-)

Yes, i welded the frame , the process is described at post #43. My second welding job in fact. Good that i was careful there, now things are much more easier that could have been with not so careful welding. used a cheap 250A Mig which i obtained from ebay+C02, hence the not so smooth welds.

[Jonathan]

How do you pour it? Just on one side and let it flow down the channel to the other, or fill both sides at the same time?

If using the self-leveling epoxy method, then the only way worth pursuing is to have a channel between the two rails (sides) and ensure sufficient depth of epoxy to flow between them. If they were poured separately, then the sides would end up at different heights, potentially resulting in significant stress on the bearings when the gantry is attached, unless shims are placed under the gantry on one side.

[Clive S]

I know that I have posted these before but this is the way I have done it. The epoxy is the Wests system Very slow cure. ..Clive

[cncJim]

Yes the magnets seem a good idea. If I was doing the epoxy I think I would have also used the thin channels, so I am sorry it didn't work out as well as you intended but I am pleased you shared the results so others (me!) can learn from it.

Sorry i thought I had seen all of the posts but I guess I have missed a lot!

[EddyCurrent]

As Jim says, the epoxy looks very good and there's no way that frame is going to move.

[Boyan Silyavski]

Now something very important. I will not move the frame at all. After a week has passed will solder the gantry and sides. Then will turn upside down the gantry and lay the upper side on the level surface of the epoxy. Then will pour epoxy on the gantry side plates that step on the Hiwin bearing blocks, connecting them together. Also pour epoxy on the lower side of the gantry beam. When dry, will turn the nagtry to normal position , rest the leveled side plates / epoxy on epoxy/ and pour the final epoxy at the top side of the gantry beam.
So with these steps i will achieve all hiwin rails lay on epoxy surfaces that are paralel to each other. The only thing left will be to ensure squareness of Z. I hope to achieve a quite precise machine.

[AndyGuid]

Now something very important. I will not move the frame at all. After a week has passed will solder the gantry and sides. Then will turn upside down the gantry and lay the upper side on the level surface of the epoxy. Then will pour epoxy on the gantry side plates that step on the Hiwin bearing blocks, connecting them together. Also pour epoxy on the lower side of the gantry beam. When dry, will turn the nagtry to normal position , rest the leveled side plates / epoxy on epoxy/ and pour the final epoxy at the top side of the gantry beam.
So with these steps i will achieve all hiwin rails lay on epoxy surfaces that are paralel to each other. The only thing left will be to ensure squareness of Z. I hope to achieve a quite precise machine.

Hi Silyavski,

Guess you have been pulled away onto other things for a while, but I really hope you will be coming back to continue with this great build thread. . . . .

I am particularly interested in whether your intended technique worked in getting the gantry rails parallel?

Cheers, Andy

[Boyan Silyavski]

Hi Silyavski,

Guess you have been pulled away onto other things for a while, but I really hope you will be coming back to continue with this great build thread. . . . .

I am particularly interested in whether your intended technique worked in getting the gantry rails parallel?

Cheers, Andy

Hi,
yes its been a while. I am not the fastest builder around it seems .


Basically what happened is that apart from other jobs and orders on my small machine, i had to change house , and it was 3 weeks madness. Now i am happyly suited in a new house with a proper garage/workshop/ so from 2 weeks i am continuing the build.

Here is what happened in short / only problems /:

1. Mistake one
I bumped the frame a couple of times when i was trying to reach the washing machine. So it moved a bit. As i wanted perfection in leveling...Only if i had hot glued the legs to the floor , this mistake will be not repeated again. So here is the solution. Again pouring epoxy, this time on my soldering jig. Waiting , fixing, pouring again, turning around, pouring. It took some time. A week.




2. Next mistakes
Then when the epoxy on all necessary surfaces on the gantry was dry enough, i decided to open the holes necessary for the bolts to hold the gantry to the bearing blocks.
WOW, another mistake. The epoxy chipped and the drill bit unglued the first of 4 epoxy plate from the gantry. Now i was worried. So i marked it and cut the corners as seen in the photo. I marked all others with numbers and crossed lines and using Dremel filed the corners. And...everything unglued. The good thing was that all was marked so i knew which is which and where it has been exactly. So i finished them, cleaned everything and using instant glue and pressure/clamps fit then where they have been.

Perfect fit, the glue squeezed equally , checked with the straight edge, well it was perfect. Hell, i was worried, and the epoxy was starting to finish




3. Painting problems

I actually bought a car paint. But as it was quite expensive i decided to base coat with anti-oxide yellow paint meant to be painted directly over the metal.

I found the following things:
-successfully painting small things doesn't mean you can paint a big thing well at home
-having pro HVLP gun doesn't help if your compressor is small and you want to paint big things. Not enough air.
-having smaller airbrush type gun doesn't help either
-not having dry filtering, i mean real dry filter on the air line , means bad things happen...
-painting yellow is a mean thing, really mean. 3 liters of paint. Well i sued a roller at the end, as otherwise i had to paint it a whole week.

in short-painting is not my strength :-)




4. Bolting the gantry to the frame and aligning the gantry rails.

Needless to say - a lot of problems.

a/ First to say i have dry bolted the gantry before painting all. It was ok. So what was my surprise when everything was painted, the machine fixed on the welding jigs for comfort and the gantry will not fit. So i called a friend that helped me and 3 times i had to lift the gantry and lower it, mean while widening the holes. The reason. This is crazy- the machine is outside, the sun heats the frame and it widens. cause i made the machine in the winter...
So basically now i cover all the time it so it could not heat . My garage is small i mean to work inside.

So at the end i squared perfectly the gantry and bolted it


b/ Now next unsuspected problem. How do i fit the rails on the gantry to be perfectly square with the long rails on the frame? I knew i could do it somehow but in reality it was a big challenge.
I know how to do it if say i make 10 same machines, a fixture and no problem. But how to do it on the cheap. Cause this machine really ate a lot of money spend on little things.
After a lot of thought i fixed the straight edge perpendicular to the base rails and decided to start with the upper rail first.
Once the upper rail was square, there came the problem with the lower rail. A friend of mine says we have all necessary stuff always at hand. So i was in no rush, thought it a whole weekend and just have done it.
Another difficulty was that i do all alone at home with no help, so first i more or less squared it using clamps and then drilled and tapped 2 holes only. Then aligned and bolted until happy. Then drilled the rest of the holes directly on place and bolted. Photos speak better than words how all of this was done.

Of course i managed to chip the paint here and there so it seems when everything is working i have to retouch it at the end. No big deal.


2 equal pieces of aluminum square bar were used to fix more or less the correct distance to the upper rail.




Both were precisely squared to the straight edge which was squared to the base rails. 2 pieces of rail were used to support them, a kind of parallels . Not seen on the pictures at the end only one was used at both sides so to make sure the fit is perfect and is really squared.




Holes were marked, 6mm drill used to clean the epoxy so it will not unglue or raise during drilling the beam, then 4.2mm drill to make the holes and then tapped. With the help of the nice little block i have.




On all drilling and tapping the gantry was clamped so it will not move around. here is the fixture which helped me align the lower gantry rail. Dont laugh at my square, had to clamp a rule to make it longer. I said we have all we need at home, just some imagination is needed.
Used thickness gauge though to align it perfectly /yes i love that word/.

Note should be taken here that when i bolted the 2 plates from the Z i pushed them from behind till they touched the screws, so i know they are alligned to the bearing blockes, as the holes are laser cut. I mean because of this i am sure that their edges are parallel with the corresponding rails. Later i will have some additional opportunity to align them on one plane/the z face plate/ as i can move one of them a bit back.


5. The result till now
I am very late with this machine. Good that my friend still suffers me :-)
Thats all for now, problems or no i am quite happy with the result. I can not say what the precision till now is, though i can say imprecision is not obvious or visible in any way. means i use precision squares and they fit well everywhere where measured. No obvious gaps or workarounds. Lets say that for sure i am still under 0.1 mm accumulated squareness. Though it took a lot of time to achieve this.


What do you think? I hope it clears some problems one could encounter on a DIY build.