Stell frame cnc 1500X1000. Adjustable table your opinion please

[Boyan Silyavski]

Hi Vagelis,
I answered some of your questions in my build thread. here is what i think for the other ones.

I I wont use a movable cutting surface as I first had in mind. The cutting surface and the clamping system will look like this.

Attachment 12675

On the 80X80X4 steel tubes I will weld 80X40X3 vertical pieces and between them 40X40 tslot aluminum profile. On the 80X40X3 steel tube, 19mm plywood will be bolted. If there is any comment I will be glad to hear it.

Your solution seems very nice, man i like it. May be will implement it in my next build. But the plywood thing i don't like. Will constantly need resurfacing if you make precision stuff.
better would be some scrap plastic sheets from doors or whatever found at the Junk yard. And on top-sacrificial layer of expanded PVC plastic sheet. Quite cheap.

Now regards the gantry it will be made from 2 80X80X4 tubes(in the middle ) and 2 120X60X4 tubes (up and down) welded together like this. At the back side of the gantry all the tubes wont be in the same plane. The 80X80 tubes will exceed 2cm to make space for the ball nut mount flange.

Attachment 12676

The ganty will be welded and then bolted straight to the hiwin carriages ( after I apply epoxy at the bottom side of the gantry ).


And now I come with my questions.
The clearance (after Deans suggestion ) from the lower point of Z to the cutting surface is 180mm. The travel of Z is nearly 130mm. When z axis is at its lowest point the situation is this




Attachment 12677


That means 6mm from spindle choke to the cutting surface.



When z axis is at its higher point the situation is this
Attachment 12678

That means 136mm from spindle choke to the cutting surface.


Is that Ok?This is very critical for the machine construction as any mistake here will need frame reconstruction. Generally is there rule about what is the distance from the choke to the cutting surface when Z is at its lower point.?

What spindle /KW?/ will you be using at the end? That make protruding things longer or shorter.
Also have in mind usual 1/8 bit is 10-30mm long, usual 1/4 bit is 20-40mm long, the piece that is not in the collet i mean.

Finally i want to ask about resonane. Is it better to use these red plates


Attachment 12679

This is best i believe:

Or it is better to use a 80X80 tube to connect vertialy left upper side of the frame with the rights upper side of the frame

Attachment 12683

Thanks for your time and i will be glad to hear any suggestion

Vagelis

What about doing longer than your table stuff?

[ba99297]

What spindle /KW?/ will you be using at the end? That make protruding things longer or shorter.

I will use a 2,2 kw water cooled spindle

What about doing longer than your table stuff?

To be honest i dont undertand what you mean. Doing longer what? The braces that the rails will be attached?

[Boyan Silyavski]

I will use a 2,2 kw water cooled spindle



To be honest i dont undertand what you mean. Doing longer what? The braces that the rails will be attached?

Longer than your bed material. The angle plate will allow material to pass. A soldered profile beam could not allow longer material.

Example: Say you are making a 3m long sign. You can do it working on one half, them moving the other half in the work area.

[ba99297]

Hi guys
Guest what?Today i start building
Here is my progress


It is too late now that i am writing
I will continue tomorrow


Thanks for your help




Vagelis

I edit the post in order to explain the photos
First of all i didnt get 6m long pieces. In order to lower the cost i choose for the lower base of the machine to go with pieces that a friend had.

Too rust but not as bad as it looks


Then i had to cut them. Good for me my friend has a big steel saw so it was easy



Bak to my home i start to make my "floor welding bench" by laying two 3,3m long pieces of steel.




I dry the rods in the oven
And i start by making the two big pieces 1,9m long as my machine has 1,9 length
The steel box section that i get from my friend pieces are 1,5 long so i had to weld them in order to make the 1,9m long that is the bigger piece.



Then i level my floor welding bench and i start


First i make the rectangular piece off the table try to keep everything square. Then i add the foot an the diagonal pieces



As i had read many times here in the forum i try to start with spot welding and not with big welding joints in order to avoid distortion. Firtsly that was easy but that make me think that the construction will have no distortion.
That was a mistake
After i finished the table ( lower part ) i realize while checking with an aluminium profile ( that supposed to be straight ) that the table has distortion issues
The following photo shows the aluminium profile when i check the diagonal from one corner to the oposite

It seems that the aluminium profile has 7mm distance from the table.
I use a jack in order to corect the bending but with no big success


Good for me i reaslize that the problem is at the midle of the table, as the 4 corner( lets name them 1 2 3 4) are all at the same level. I use a digital level. First i messure τηε gadient between corners 1-2 and i zero the level. Then i continue by messuring the relative gradient f between corners 2-3, 3-4, and the diagonals 1-3, 2-4. All the messurement show 0.0 gradient. Also 0.0 relative gradient i messure between the front and the back beam. That i s good as i can correct any mistake at the next steps (weld the upper 1,9m long beams where the rails will rest) before i apply epoxy.
Now i am waiting for the 6m long beams to contruct the rest of the table



The big problem till now is the weight of the table.
I can hardly turn it upside down
Tomorrow i will put a winch on the ceiling in order to deal with the weight that will be more than 300kgr ( without the gantry)

Thanks for your time

Vagelis

[EddyCurrent]

Looking good. Once you have the frame finished the build moves along quite quickly provided you keep it going. Try to order your materials in advance because it felt like I spent a lot of time waiting for things to arrive in the post.

[ba99297]

Hi everybody
This is the table so far ( the piece in the middle with be removed a little bit)



This is how it will be



Two questions

#1 If you see the the top right photo you will see that i dont make a full welding pass just 3 spot ( edges and at the middle ) in order not to produce too much heat. Is that ok or should i weld all the way?

# 2 Do you think that more diagonal support will be needed and where?


Thank for your time

Vagelis

[Boyan Silyavski]

Two questions

#1 If you see the the top right photo you will see that i dont make a full welding pass just 3 spot ( edges and at the middle ) in order not to produce too much heat. Is that ok or should i weld all the way?

# 2 Do you think that more diagonal support will be needed and where?


Thank for your time

Vagelis

Hi Vagelis,

#1 I believe what is below the gantry and the gantry itself should be fully welded. Anyways later you will epoxy it for leveling. I spot welded only the Z which seemed strong enough/on my build i mean/

# 2 To me it seems there would be no need, especially with your monstrous table bed

[njhussey]

#2 I think you could do with some triangulation horizontally to stop twisting but apart room that it's looking good!

[ba99297]

silyavski thanks for your comments. I dont forget your help so far.
Thanks.
You have inspired me many time with your work and your suggestions

#2 I think you could do with some triangulation horizontally to stop twisting but apart room that it's looking good!

When you say horizontally you mean at the corners of the table?


Vagelis

[njhussey]

When you say horizontally you mean at the corners of the table?


Vagelis

Yes that's it, on the inside corners...