Sturdy and Fast all Steel CNC , my first build

[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.