Sturdy and Fast all Steel CNC , my first build

[Neale]

Welding and Epoxy leveling make steel frames very easy and cheap to achieve.

That's what I'm hoping!

[Boyan Silyavski]

Hi there,

I would like to point again that the further i go building the machine, the more discover how important and later time saving was to weld the whole machine with under 1mm, even possibly under 0.5mm precision.

I would like also to remind you that i welded the machine fully, but it took like more than a half of day, due to waiting things to cool and the having in my left hand the IR remote thermometer, controlling that the overall temperature of the frame and gantry stays under 60C. So any change of dimensiones was successfully avoided.
So if you don't have thermometer at hand, just wait untill cool to the touch. And no more than 2 inch at once, always mirroring.

Here is some more progress in details.

The Hiwin are wide 20mm, i made the epoxy 40mm wide, hence-10mm each side. Thats should be the proper way. The meniscus took like 3mm at least.
So how i dealt with the meniscus? I decided i would not waste time on it, so i glued sand paper to a stick and started sanding it off. Not completely. I decided i will mount the rails and then continuing with epoxy leveling the gantry rails and side supports.
In other words dealing completely with the meniscus is a waste of time. The process took me 20 minutes, the epoxy sanded like a snow flakes. 20 min more for the end of the epoxy, where the end of the rails would be. here i checked with straight edge and scraped a bit the last cm.
It is a very good idea to stuck a tape over the middle of the epoxy, where the rails would be, as not to scratch it!




Well, it seems it worked as supposed. The epoxy i mean



Buying the precise 1m straight edge and precise square was a very good idea. In a matter of minutes i placed and aligned the rails. I would say that its crucial .
Both cost around 100 euro and a week research , see here: http://www.mycncuk.com/forums/tool-t...-straight.html




Once in place and squared i rechecked them using a long steel ruler made from 2 rules and magnets, which i fitted inbetween and checked at both ends. Tight fit as expected. I supported it with alu beam so it would not bend/ like in the picture, while i was making the shot/








Just a side note here. Forum is ok, but read the frigging manuals. Hiwin rails have direction, also the carriages/ its not seen on the pic, but the letters should be at the side where the arrow points to/ . have that in mind, is buried somewhere in the long manual.




I was tired and working after work. But i wanted and started to feel a kind of satisfaction not being in a hurry and doing things right. So instead of drilling through the clamped hiwin rails, i used a hole transfer tool lightly using the hammer. And a torch, to see better.




And as i started to feel that satisfaction, i decided to continue accordingly the process, drilling first 3mm holes, using the very handy tool to keep them vertical.
The torch helped again to see things , illuminating the epoxy from below.



Some holes and here is what happened. I had to go for a new drill, as it seems if the drill is not perfect, it adds heat and the epoxy lifts around the hole. Not a big deal, will scrape it with a small straight edge. The epoxy scrapes nicely, as i said-like snow flakes



Now i am waiting for a new brand M5 tap and the bolts for the Hiwin to arrive. I wouldn't risque with the cheap tap i have. I bought them from internet as it seems that screws are quite expensive locally.

Thats all for now.

[GEOFFREY]

Coming on nicely nicely now, looking very good, but I wouldn't expect any thing else having read your build log and your obvious attention to every detail. Great stuff. G.

[EddyCurrent]

Obviously section 1.10 of the Hiwin manual is the 'correct' method but if you don't have the gear . . .
To mount rails similar to yours, I first clamped a straight edge along the top with the edge parallel to the beam and for the Hiwin rail to be in the centre.
Then I clamped the Hiwin rail to the beam making sure it was tight up against the straight edge. The holes in the rail are about 5.5mm diameter so I used a 5.5mm drill in every mounting hole to make a dimple in the epoxy similar to using a centre punch. This allowed my 4.2mm tapping drill to go right through the epoxy and beam, all central to the Hiwin mounting holes. The other rail was mounted in a similar way but using a DTI gauge to keep them parallel.

[EddyCurrent]

After your problems it's looking nice, I like the colour.

[Lee Roberts]

After your problems it's looking nice, I like the colour.

+1

[ba99297]

Syliavski nice work. Congladulations!!!!
How thick steel plate did you finally use and what is the weight of the gantry ( so far without Z axis)?

[Boyan Silyavski]

After your problems it's looking nice, I like the colour.

Thanks! I like to discuss here in detail the so called "problems" , not cause they are real problems, especially for a metalworker with the proper tools, machine and workshop.

I would rather say difficulties for the DIYer on the cheap where solutions have to be with what you have at hand and at the same time aiming precision.

What did you use to build the dams to hold the epoxy? I can't quite make out the detail in the photos.

Some post back you can see it on the photos. Alu angle profile, 10x10x1mm x 1m, very cheap. Instant glued to the frame and then hot glued from outside.

Its seems the epoxy is ok, as far as common sense is used, the profile is clean and 10mm margin is left from the bearing rail, as it/the epoxy/ tends to rise 5mm from the contact point with the margin, whatever the material.

PS:
-When lifting the angles or whatever you use to form the dams , it is wiser to clamp here and there the epoxy and always take care not to lift it ,break it or chip it.
-when drilling for the rails which for example are screwed with M5 screw, first mark the holes, drill with 6mm drill then center 4.2mm drill, drill and the tap M5. So the epoxy around the holes will not bother you, lift or chip, or heat and lift.
-with time , especially temperature changes can make the epoxy very easy to unglue. Clamping it is necessary in this case.

+1

Thanks! Great forum :-) and a lot of help.

Syliavski nice work. Conglatulations!!!!
How thick steel plate did you finally use and what is the weight of the gantry ( so far without Z axis)?

10mm steel plates, laser cut. Laser cutting the holes saves a lot of fiddling but care should be taken cause some long and thin section parts are not perfectly straight on their surface plain, so should be checked against straight edge where necessary and plastic mallet used to straighten them.

Now looking back at the drawings, instead of 0.5mm and 1mm bigger than the respective M screw size, i would advise at least 2mm bigger diameter. The paint eats it, the straightness eats it, adjustment eats it, so i constantly had to mount, check, unmount and open more the holes. Say if you have M6 screw, the hole from the beginning should have been 8mm diameter

[Lee Roberts]

Thanks! Great forum :-) and a lot of help.

Hi,

Your welcome Silyavski, from your build log came great discussion and realisation for others.

So, thank YOU for sharing your adventures and returning help to others, the results are a great forum and community.

In unity everyone can be successful, this is my original goal.

.Me

[Neale]

What did you use to build the dams to hold the epoxy? I can't quite make out the detail in the photos.