Stell frame cnc 1500X1000. Adjustable table your opinion please

[ba99297]

That sounds a little dry - do they have any grease in the carriages??

2.7kg also sounds tight - if this is a truck on two parallel rails, i would slacken the screws on one rail, fit the carriage/plate etc and the gently tighten the screws as you slide the carriage assembly along. Also the same for the screws holding the carriages to the plate - slacken and tighten them with the assembly in position. This allows all alignment stresses to be released hopefully.

Still sounds like it needs grease though, my HiWin stuff was very quiet.

Yes you are correct, I haven’t put any grease yet
Is there any special type of grease for these carriages, or a general purpose grease can do the job?

[Lee Roberts]

Yes you are correct, I haven’t put any grease yet
Is there any special type of grease for these carriages, or a general purpose grease can do the job?

A general purpose Lithium 2 grease will do just fine:

A Premium quality mineral oil, lithium thickened lubricating grease suitable for general purpose applications in plain and anti-friction bearings.

Conforms to leading bearing manufacturers specifications for general purpose industrial and automotive grease.

.Me

[ba99297]

Hello everybody and happy new year
I reastart my project that has been stoped for more than 6 months
I finally epoxy level X axis and i will do the same with the y axis (the gantry) as the milling of the gantry wasnt as good as i expected
I will apply two layers of epoxy 4mm each.

Many off you may wonder why i go with two layers of 4mm instead of one layer 5mm.
To be honest this is the second try of epoxy level the gantry
The first try went wrong
It wasn’t the resign as i had no problem with the x axis leveling
The reason off the first fail was this


After having the gantry milled there was a 3mm groove for the master rail.
At the first epoxy try the groove had been covered with epoxy so the epoxy had 5mm thickness above the groove and 2mm thickness next to the grove. i don’t know if i am understood.
So at the second try i choose to cast two layers. The first one will cover the groove and cover the 3mm gap and the second one will be layed on a flat surface.
Today morning i start with the first layer
First i put the gantry lay on the x axis blocks as x axis is perfectly leveled after the epoxy method



I zero my dial gauge in order to level the gantry parallel to X axis.
The 1.9 degrees tilt that the gauge show is a permanent error after an accident




In order to achieve perfect level tuning i use some screws as jacks


I knew that i couldnt have zero level at every point of the gantry as the gantry is not true flat. I was trying for an average zero level.


All the previous night i use an electric heater to rise the temperature to 20-21 celcious

Today morning i start creating the dome

I use both mdf and foam



Here is the epoxy i use


More than 10 hours working time
300 mpas viscosity
Pot life 29 hours (70 ml at 23c)
and here is the data sheet
http://www.resoltech.com/IMG/pdf/DS_...21.07.2016.pdf


Price 36 euros




Thanks for your time
Will be glad to read your comments

Vagelis

[ba99297]

48 hours at 20 co after casting the first epoxy layer (4mm thick) is sticky and starts hardening.
Today morning 8-1-2017 I apply the second layer (also 4mm thick)
Things seem to be ok.
The epoxy is transparent and clear as glass
After full curing I will upload photos.
Mean while (until the epoxy hardens) I will start working on Z axis

Vagelis

[Clive S]

Make sure you let it cure for at least 10 days if you have made a sample mould then when you try and bend the epoxy it should snap like glass and not bend.

Not sure why you need 8mm thick?

[ba99297]

Not sure why you need 8mm thick?

Thanks for your answer Clive
I know that 5mm thick is enough but as i said,"...After having the gantry milled (a process that went wrong) there was a 3mm deep groove for the master rail.

At the first epoxy try the groove had been covered with epoxy so the epoxy had 5mm thickness above the groove and 2mm thickness next to the grove. So this uneven surface may cause the failure of the first try. That is why I decided to go with two layers casts. The first one will cover the big error so that the second one will do the level job better. I don’t remember where, but I had read that in some way the epoxy follows the initial surface and corrects a big part of the surface error, but not all the error.
That is why i choose to cast two layers (4mm each).

[Clive S]

Sorry I did not read your previous post properly. I take it that you are using the epoxy to level two rails up if so you need a moat between them

[ba99297]

if so you need a moat between them

If you see the photos that i upload, i already have made two moats, at the edges of the gantry

They are the white extensions left and right of the gantry
It is like a cyrcle. All the epoxy surface (underneath the rails and the moats) are 50mm wide
Thanks Clive

[reefy86]

Yet another bloody post i spend reading for it to hang dead lol, How did it go for you in the end?

[ba99297]

Big restart after 4 year
This is the second BIG RESTART on a project from 2014. I hope that this will be the last restart
Glad to be back to mycncuk. I have this project running since 2014.
In my last post back to 2017 I was “epoxy leveling” the gantry
Epoxy correct most of the error BUT checking the carriages with straight edge I found out that the rails are twisted (I don’t know if my English are correct). So shims should be used.
I wander if everyone that uses epoxy method ever check the machine against straight edge?

It was a painful process but I learned a lot about shimming
Some photos of my progress till now




Just to remember some basic specs of the machine
Cutting Size 750X1200
Ballscrews x,y axis 2010 z axis 1605
Gearing 1(motor):2(ballscrew)
At first I was planning using three motors (one each axis X,Y,Z) so I bought a set of three Yaskawa servo motors 400 watt, one of them with brake. After many suggestions and advices I finally bought another 200watt Yaskawa for Z so I have
2 X400 watt for x axis (long)
1X400watt (the one with the brake) for Y
1X200 watt for Z
Here is a picture of the motors


My main concern is if 200 watt servo with 1:2 gearing and 1605 ballscrew is enough to handle z axis that is nearly 25-30 kgr (assuming that gearing and ballscrew pitch will 4X the torque of the motor)
Last days i work on attaching the ballscrews so I can mount the motors and see what pulleys and belts I have to order (htd5 15mm wide). Are the Chinese ebay pulleys ok? Do you have any reliable supplier. Do I have something to be carefull. Here is my last progress





So i repeat my questions
#1 Is 200watt servo enough for z axis
#2 Pulleys and belts.a) What to be carefull about, b) reliable supplier

Thanks for your time
Vagelis