Stell frame cnc 1500X1000. Adjustable table your opinion please

[vargai]

I didn't measure this directly. It's based on a difference in heights of rail of 1mm and a rail spacing of 1m. Looking at the hiwin catalogue, I think they say that the bearing blocks can tolerate a slight rotation around the rail, and a height difference of 0.26mm (20mm rail, 1m spacing). This is a lot more than the figure that Silyavski has given, but I might have misunderstood something.

Only the 1 micron (you wrote 0.001mm) seemed to tight. The angle is correct, the level deviation on 20 mm is 0,02 as my dwg says
It is one magnitude bigger but I do not think it has too big impact on a router-by the way I would not be satisfied either with 1 mm on 1 m because deviations accumulates according to the Murphy catalogue

[Neale]

Perfectly correct, Vargai - I forgot to multiply the "1 in a 1000" ratio by the width of the rail. I've slapped my own wrist...

[vargai]

Perfectly correct, Vargai - I forgot to multiply the "1 in a 1000" ratio by the width of the rail. I've slapped my own wrist...

I would not have intact body portion so just meant to understand you

[ba99297]

Hello everybody
I am happy that i restart my project
Many things had happened during the last year, that make me stop any kind of progress
That until August when i decide to restart, but first i had to make some changes in my working place
The most important was that the floor was worn and all these years was a source of dust.
That was the situation before


I decided that i must lay tiles and keep one place with some kind of heavy duty concrete, in order to be able to weld, as tiles even if they are very hard though they are not suitable for such jobs
First i had to clear the floor from old paint
Two days of water blasting with my karcher finally make possible this


Then i begun to lay tiles

It was the first time for me that i lay tiles in such a big scale ( 80 m2), and i lay them diagonally
Finally the result is this



I had the chance to paint. I decide to paint with oil paint the first one meter and the rest with water color

Then i had to make the "baby room". Yes thats right!!!! the place that i will put the cnc. I had some old aluminum doors and i dont want to sell them for scrap. I also had some drop ceiling parts, so i use them all and i made this

Yesterday i move the frame and all the components in order to restart building


As you can see the machine is rolling on 4 wheels. That makes the removal of the machine very easy
Finally the "baby" get in the new house

So Today i start working again on the machine.
Nice feeling
First i had to cut some ruber parts for the adjustable feets


So far that is my progress
I will continue tomorrow
Thanks for your time
Vagelis

[JAZZCNC]

Looking Good Vagelis. Nice and cool. . .

[ba99297]

Dean thanks for your good words
As more than a year has passed since my last attemp of rails intalation, today i go on
I had some questions that i wrote 1,5 year ago (30-11-2014 #171).
I repeat them in order to understand what level of accuracy i have to achieve

--------------------------------------------------------------------------------------------------------------
#1 ( very important to know what I am trying for )
When you measure the flatness of a beam ( or epoxy surface) against a straight edge, what is the acceptable tolerance-gap ( so we assume the surface is straight) . I use light to understand whether my top beams attach the straight edge. The touching points can be easily seen. But at other points althought i can see that there is no touch ( light passes through) , the 0,02mm Gap Filler cant pass through the gap. So what is the critical gap ? the light passing test ( that is less than 0,02mm ) or the 0,02mm gap filler test?

#2
When someone use the solution with the adjustable top beams ( without epoxy) or the shimming method how does he succeed to have the top rails in the same plane. How does he know when the two rails ( left and right ) are in the same plane?

--------------------------------------------------------------------------------------------------------------
Hiwin maual (among others) has this table that says ( if i read right the table) that the height H of a rail has a range +- 0.1 mm for normal accuracy rails



Thanks for your time
Vagelis

[ba99297]

A little progress today
This is a try to level my cnc before i go on with hiwin rails.
I use an aluminum spirit level and a digital Protractor Inclinometer that has a permanent tilt of 2o against earth level ( upper value on lcd screen) after it dropped from my hands.
What is important is the relative angle
Here is the result.
If somebody has something to say about the previous post #186 questions, i will be glad to hear

Thanks for you time
https://youtu.be/2yhukWVv7NQ

[Boyan Silyavski]

Dean thanks for your good words
As more than a year has passed since my last attemp of rails intalation, today i go on
I had some questions that i wrote 1,5 year ago (30-11-2014 #171).
I repeat them in order to understand what level of accuracy i have to achieve

--------------------------------------------------------------------------------------------------------------
#1 ( very important to know what I am trying for )
When you measure the flatness of a beam ( or epoxy surface) against a straight edge, what is the acceptable tolerance-gap ( so we assume the surface is straight) . I use light to understand whether my top beams attach the straight edge. The touching points can be easily seen. But at other points althought i can see that there is no touch ( light passes through) , the 0,02mm Gap Filler cant pass through the gap. So what is the critical gap ? the light passing test ( that is less than 0,02mm ) or the 0,02mm gap filler test?

#2
When someone use the solution with the adjustable top beams ( without epoxy) or the shimming method how does he succeed to have the top rails in the same plane. How does he know when the two rails ( left and right ) are in the same plane?

--------------------------------------------------------------------------------------------------------------
Hiwin maual (among others) has this table that says ( if i read right the table) that the height H of a rail has a range +- 0.1 mm for normal accuracy rails



Thanks for your time
Vagelis

#1
For me its very simple. Depends on table size. For under 1m everything more than 0.05 anywhere is unacceptable. For bigger tables 0.1 deviation on height is the limit. So hiwin is right.
Now i want to tell you that it took me a week to mount my 2 long rails . I mounted them and dismounted them 5 times, not counting the 3 pours of epoxy. So at thend depends what you will use the machine for.

My standard is very simple. if i can notice a gap with naked eye, its unacceptable. Be it 1m or 10 meters table.


#2
yeah, thats why i dont like this method. Ask Dean. But it should be possible if you of course have straight edge that can lay on top of both of them at the same time. i doubt though you could achieve same precision as with epoxy

[ba99297]

Boyan thanks for your answer.

#1
For me its very simple. Depends on table size. For under 1m everything more than 0.05 anywhere is unacceptable. For bigger tables 0.1 deviation on height is the limit. So hiwin is right.

I guess when you measure in mm, so when you say 0.05 you mean 0,05mm and when you say 0.1 you mean 0.1mm right?

So even if i can see light pass between the rail and the straight edge but the 0,02mm filler strip can’t pass through the gap you think is OK for a 1800mm long table?
Really after epoxy cure, when you attach the straight edge on the epoxy surface is there any gap between the epoxy and the straight edge? The epoxy surface is perfectly flat against the straight edge? If the answer is YES i have an idea here

http://www.mycncuk.com/threads/9511-...t-work?p=76521

Vagelis

[Boyan Silyavski]

Yes, i meant in mm. But to tell you the truth i found that the hardest thing is to avoid for dust not to get trapped in between when mounting, cause that could f%%ck all previously achieved precision. When i lay the rails i lay the edge first and scrap them against the epoxy so no dust goes trapped there. And there is a lot of particles of it even in a new workshop :-)

My straight edge was perfectly flat against he epoxy when i was happy with the result. But even in my best result, at one end of the bed under one of the rails there was need to shim / if you read the whole thread about my machine you will remember that i was experimenting a lot with the epoxy pour, so i found the way to do it properly/

So yes, to your idea about the DIY epoxy straight edge, but remember the main thing i discovered when pouring 3m rails, i needed to over extend the epoxy both sides 25cm/?? read the thread again but make it so to be on the safe side/ so it shrinks there, after that just cut it to the size of the profile.Similar to what you will do with the meniscus.