Stell frame cnc 1500X1000. Adjustable table your opinion please

http://img.tapatalk.com/d/14/07/23/eby2yqe8.jpg

Like that...but hopefully with better welding...

Or like this;

http://www.mycncuk.com/threads/6565-...2425#post52425

New photos of the progress
Yesterday i cut the steel and the aluminum pieces for the bed
Attachment 12879

I install a winch at the roof , as the weight of the table is big ( nearly 140 kgr so far) to handle with my hands
I turn the table upside down to full weld all the joints
Attachment 12880

I remove the middle piece as i change my plans. Another three pieces will be welded vertical to the sides of the machine

Attachment 12881

I put temporary the steel and aluminum pieces of the bed to get an idea how the machine will looklike
Solid works is very good but the real world even better.

Attachment 12882Attachment 12883

I will use epoxy for the rails level but i try to be as precise as possible.
I chek the level of the table and the results are very good
I use two diagonal threads that they just touching each other ( that means the orners are at the same level)
Also i use a digital level that shows RELATIVE ANGLE between the diagonals 0.0o.

If you see the videoa the absolute angle is 2.0-2.1. That is not a real mesurement as the level fall from my wifes hands and has an offset 2.0o. That is not matter as what maters is the relative angle
Here are the videos

http://youtu.be/3d5rWFlVGiQ

https://www.youtube.com/watch?v=mZRs_tw1Dv4&feature=youtu.be

Coming along nice Vagelis. Don't waste too much time on trying to level just yet until your ready to do the epoxy leveling. Removing twist is important and it looks like you are doing a good job here.

I would put some more supports under the Bed. Even thou your using steel it will resonate if it's not supported in the middle. I would put 2 more pieces in there.
Also like as been said braces in corners to help keep square won't hurt.

Much nicer feeling building than designing isn't it. . .Lol

Thanks for the comments.
Even so far everything is ok i had some issues wtih the gantry and i want your opinion

I plan to build the gantry with 2 pieces 120X60X4mm and 2 pieces 80X80X4mm so i would make sometring like that

Plan A
Attachment 12885 Attachment 12886

but i realize that the 120X60 tube is 3mm and not 4mm as i thought. So i think that i may have resonance issues.
TO be more specific at the front of the gantry 10mm steel plate will be welded so finally it will become like this

Attachment 12887

Plan B
With 2 pieces of 120X60X3mm tube at the top and the bottom and 4 spacers 120X60X3mm 160mm long
Attachment 12888Attachment 12889


Plan C
Two 80X80x4mm tubes at the top and bottom and a 120X60X3mm at the middle. May move the 120X60 tube 2cm to the back so to have room for the balnut flange

Attachment 12890 Attachment 12891



All thre plans will have the front 10mm steel plate as shown at plan A
All three palns have 280mm gantry height

Plan D
Three 80X80X4mm tubes with the middle tube offset by 4cm to leave room for the ballnut. This will reduce the gantry height to 240mm and i dont know if it will weaken the machine.

So my questions are
1. which of the above plans would be better?
2. Assuming i will put the rails at the front do you think i can reduce the gantry height ( according to my plans it should be 280mm and nearly this should be the distance between the out face of the carriages of y axis). Plan D reduces the gantry height to 240mm. Remember that the length of the gantry is 1160mm.


Thanks for you time

Vagelis

Dont be in a rush with it. better think it again. from various angles.


Now a couple of questions which are related:

-Why the 280mm height? Did you purchase already the rails for the Z at certain length?
-what is the width of the Z carriage plate that slides on the gantry?

Because i believe that it can be made narrower and that bearings with some thought to go behind the Z, not to eat of your Z travel left right/x axis/.

-what about the total weight of the gantry? you are not going with servos, right? this frontal plate will weight a lot. Actually i don't like it for that reason. You can strengthen the gantry in other ways. For example plan B and fit triangles inside where the vertical pieces are and no face plate. If the vertical pieces are spaced ~30cm or less there will be no need at all for face plate.


I was personally for plan B, but... Check again all the details, may be a mix of them all. Cause now looking at my drawings in fact i see B impossible as you draw it, cause you only need 40mm of the ball screw support to go inside so the ball screw housing barely shows, but in that case the rails should go inside the profile, which is impossible. So may be draw it first. To me it seems that C is closest of all to the measures . Just move back the middle piece so its 43mm back from the front.
You can reinforce it like this/ the middle profile in your case/ :


Attachment 12892


I cant remember if you have already bought the ball screws and the rails, if not-fit that motor inside as i told you at the beginning :-) and save some money for beer :-)

Sylyavski i answer your questions to make things clear

The 280mm height is the result of the conevrsations that i had at this thread. They advice me to have minimum distance betwen the outer face of the carriages 250mm. So i make combinations wtih 120X60 and 80X80 tubes to get that height. So two tubes 120X60 at the top and bottom and two 80X80 give me the 280mm

The width of the z axis carriage plate is 370mm. Even if i narrow it as you suggested, i wont get more y axis travel as the spindle plate will conflict with the bottom steel plate ( where x axis carriages will be bolted.

The total weight of the gantry so far is nearly 140 kgr
I will use servos. 4 yaskawa sgmph 400 watt each ( two of them for x axis). 2010 ballscrews for x and y axis, 1605 for Z. 2:1 geat ratio for all axis ( 2 at the ballscrew 1 at the motor. Htd 15 with 5mm pitch aluminum pulleys.

Rails carriages, ballscrews, motors and spindle (2,2 kw) are in my hands. So no change can be made at these components.
If there is any suggestion i will be glad to hear

Vagelis

I get it now. Then maybe you could look at my last post in my next build and consider how I am making my gantry http://www.mycncuk.com/threads/6619-...0346#post60346
May be you would like some of mine ideas which i belive will lead to very strong gantry with no overhang and exclusively made from profiles, like the ones you have. That's the best I have come till now.

Here is my progress the last two days.
Yesterday all the day pass drilling and taping the bed and the table for attaching the bed
Attachment 12913
Attachment 12914
Attachment 12915Attachment 12916
Attachment 12917

And that is how i end up today
Attachment 12918


No time to write. It is too late... Sorry
Tomorrow

Thanks


Vagelis

Today progress
I have to weld the upper 80X80 pieces ( where the rails will rest )
The lower pieces ( over the foots) make i little curve ( nearly 5-6mm ) at the middle as reult of the heating.
So i decided to weld 4 spacers at the corners. Put the upper pieces with spot welding after make everything square and parallel as possible
Here we are
Four spacers 120mm at the corners
Attachment 12957 Attachment 12958

Then i put the upper pieces and before i spot weld i try to make everything square. I use the 1160mm pieces (this is th excact distanse that the upper 80X80 pieces should have) that i will use for the gantry, and other parts of the cutting bed to make everything parallel

Attachment 12959 Attachment 12960Attachment 12961 Attachment 12962Attachment 12963

After having the tubes as parallel as possible i messure the excact distnace and cut the rest of the spacers. Then i spot weld from the middle to the corners. After everything was in place i start to full weld the table. In order to avoid too much heat i make 2-3 cm welds at a time from one spacer to the other and from the on side to the opposite. So i pass along the table 20-55 times( welding and cleaning the welds). In order to have better welding results i rise the table to have better angle
Attachment 12964Attachment 12965Attachment 12966
End of the day and after turning the table upside down to full weld all the sides, i think the result is more than acceptable
Attachment 12967Attachment 12968Attachment 12969Attachment 12970
0.0-0.1 radius ( messured at different spots) the offset between the upper rails and the vertical pieces.
This offset will be zero after epoxy ( ...i hope so )


Next step is to make the tuning foots. That is why i weld a 80mm piece at every leg with a hole in the middle to pass the m18 bolt.
Attachment 12971
Then the epoxy method will take place

Till now i think it must be nearly 200 kgr. The winch save me from a lot of work
Thansk for your comments
P.s Do you think that the legs should be connected at the lower part of the table?

Vagelis

Looking good, I think the legs are okay as they are. Make sure you paint the frame before doing the epoxy, it's a lot easier, but leave just the top surface of the upper rails bare metal so the epoxy sticks good.

Starts to look very impressive. Nice job. I envy you for your big and nice looking workshop.


-In my opinion you don't need to adjust the table by bolts. The machine needs to be sturdy at earth level. I plan to buy for mine 6 hockey plucks. That's what my friend did and works like a charm. Not needed, but he is a maniac.


-if you follow what Eddy said and paint it, may be don't paint also where the ball screw end supports will be. When the gantry is mounted, then fix the ball screw, then go to one end and then tack solder the fixture for the end support, then go at the other end and repeat. Then remove the ball screw and then solder it carefully there. So when all is ready in the same manner you rectify the ball screws. Cause if you solder now, later may be there would be need to re drill the holes and waste a lot of effort. That's my way of course.

Thanks both for your valuable advices.
Syliavski when you say NOT to adjust the table by bolts, what if there is any imperfection 1cm at the floor ? The hockey plucks that you suggest will be welded at the frame. What material are made of these plucks?
When you are talking about the balscrew fixture end support, you are talking about X axis? If you see my plans i am going to attach the fixture to the frame with bolt so it will be adjustable.
As for my work shop thanks for your comments. There is my paradise. Music, creation, and no one to bother me.

Quote:

---

Originally Posted by ba99297

As for my work shop thanks for your comments. There is my paradise. Music, creation, and no one to bother me.

---

Nice, where I am it's mostly pissing down with rain.

I bought M25 or so bolts for the machine, soldered the nuts to the legs, thinking that will hold. When the machine was ready i left it on the nuts only and they lay on the hockey pucks. cause i did not find M25 bolts sturdy enough. On your machine M25 6cm bolt on the legs will shake like a plastic, once that heavy gantry starts accelerating.

The pucks are made from hard PU rubber. make sure they are the solid ones, not refilled with something.


You call 1cm imperfection :joker: , i have to deal with 6-7 cm inclination in my garage and i plan to level it with cement. Thats what is best to do, to level the floor under the machine. If i had to deal with 1cm, i would simply stick 10mm steel plate below the leg.


Translate for you design:
I meant these pieces in blue Not to be welded until the gantry is ready and mounted and rectified in all directions:
Attachment 12974


Then bolt these 2 together with a piece of paper between them/that for the later paint thickness
Attachment 12975


Then bolt all that is in blue together as it would be at the end, trying all bolts to be in the center of the holes. the bolts must not be tightened very much
Attachment 12976


Now move to one end the gantry and spot weld with 5- 6 spots 1 of the pieces in blue from the first picture. Rotate by hand the screw and move to other end of machine. Now you spot weld the other fixture.

then dismount all in blue, ballscrews , etc. Then weld well the 2 fixtures. No everything is in parallel/guide rails and ball screws/ and perpendicular/ball screw supports.

When painted and ready, mount them the same way. So the only necessary adjustment will me made by the play of the bolts that hold the ball screw end supports to the fixtures. Tighten them when gantry is at that end.

In other words, now all 2 rails and 2 ballscrews are exactly parallel and have exactly same travel. Doesn't matter if one is up or down, otherwise using other method that also should be taken care of.

PS. Somebody has to hold the screw not to bend by its weight and the weight of the fixture

Silyavski thank so much for your time and your help
Also thanks for your plans and your colored designs
I will make the legs ( they wont be 6cm long) i will make them as sort as possible
I will use them to perfectly level the machine while apply the epoxy at x axis, and if the floor is leveled when i pu the machine at its final position, i may only use shims

Thanks again

Vagelis

Ps:My ballcrew end support fixtures wont be welded but bolted at the frame so it will be possible to make small adjustments

Hi everybody
Here is my last week progress
Firstly i get the bolts and the steel pieces laser cutted last Friday
Attachment 13035Attachment 13036

In order to save money i didnt laser cut the holes ( wherever needed ) except the straight slots. I just ask to point the center of the holes
So i use these centers and then i drill the holes

Attachment 13037Attachment 13038Attachment 13039

At the following photo you can see two pieces that will be bolted together. The upper piece will be welded with the gantry tubes and then it will be bolted with the lower piece. The holes of the two pieces should be excactly coeficient so i drill the upper piece an the i put the one piece over the other to mark the ceter of the holes
Attachment 13040Attachment 13041
After pointing the centers i had to drill the holes. That took me A LOT OF TIME. Even more time i need for the tapping
Attachment 13042Attachment 13043Attachment 13044

Today i start the adjustable foot construction. Syliavski suggest me not to put that foots. Even if i use them or not they are very usefull to level the table as perfect as possible for the epoxy method. You will see each foot has 4 holes. The one at the center is for the bolt the other two ( the smaller ones ) are to bolt a softer material at the side of the foot that touch the ground. The fourth hole is for bolting the foot at the floor


Attachment 13045Attachment 13046Attachment 13047Attachment 13048Attachment 13049

Then i lift the table with the winch and put the foots
Attachment 13050Attachment 13051
https://www.youtube.com/watch?v=S1RO4O7IUfc
After that i go on with the tapping. Too much time but the result was more than good
Attachment 13052Attachment 13053Attachment 13054Attachment 13055
After i bolt the side parts i start to work with the gantry. I put the two side braces on the table and then i attach the vertical 10m plate.
Attachment 13056Attachment 13057
If you can see the stell plate has two projections ( left and right ) that will "sit" at the side braces so that the distance will be driven by these slots. It is something like a tagram.

Attachment 13058
Then i use long bolts to "tune" the gantry

Attachment 13059Attachment 13060Attachment 13061
At the follwing video you can see how everyhing joined nice
https://www.youtube.com/watch?v=SvcRhIGgUe8
At the above photos you cant see the gantry tubes, as i put them later. But you can see them at the follwing video where i make a level test
https://www.youtube.com/watch?v=Q90-rIGHBj8&feature=youtu.be

This is my progress so far. Tomorrow i will bolt the front steel plate at the tubes and weld the tubes with the internal side plates

Thanks for your time
I will be glad to here your comments

Vagelis

The laser cut parts look great, I like how the holes have been marked with both a centre and an outline of the hole. This is good engineering practice and I don't know if you already know this but if the drill moves off centre this is how to bring it back into line;
If the outline of the hole had not been marked you would not know if the drill had moved off centre.

https://www.youtube.com/watch?v=ESWzx3YBo3g

Quote:

---

Originally Posted by EddyCurrent

This is good engineering practice and I don't know if you already know this but if the drill moves off centre this is how to bring it back into line;

---

Nah good engineering practice is to do it right first time and use a proper spot drill not some poxy pin prick mark.!!

Looking Good Vagelis don't drop it on your toes mate. . .Lol . . . . . .Drilling & Tapping 100's of holes in 10mm steel is good for building character and stamina needed to setup and run CNC machine. . :thumsup:

Quote:

---

Originally Posted by JAZZCNC

Nah good engineering practice is to do it right first time and use a proper spot drill not some poxy pin prick mark.!!

---

That is correct but it's not what I said.

I said, ". . . the holes have been marked with both a centre and an outline of the hole. This is good engineering practice . . ."

I know this because I have served a proper engineering apprenticeship when things were done right.

One small problem
I phone the supplyer of west system resigns here in Greece and he told me that for 105 resign he only has the 206 hardener and not the 209 ( that is recomended by the members here in my cncuk). Do you think that i can do my Job with the 206 hardener and not the 209. The temperature here in Greece is 32-35 and nearly 25-30 at my worklace.

Thanks

Quote:

---

Originally Posted by ba99297

One small problem
I phone the supplyer of west system resigns here in Greece and he told me that for 105 resign he only has the 206 hardener and not the 209 ( that is recomended by the members here in my cncuk). Do you think that i can do my Job with the 206 hardener and not the 209. The temperature here in Greece is 32-35 and nearly 25-30 at my worklace.
Thanks

---

I have used the Wests System and spoken to them a couple of times. I think you really need the 209 as it has a very slow cure and that is what you need for the resin to level out. I purchased mine here : http://www.ecfibreglasssupplies.co.uk/ not many suppliers appear to stock it but can order it for you. ..Clive

I agree, i don't see how it would be done without the proper hardener.
I purchased mine from http://www.dansonmarine.co.uk/ and he shipped 2 packs to Spain for 17GBP for 3-4 days.

Maybe buy locally the epoxy and purchase only the hardener, have to check with them though.

For the Hiwin 20 rails the minimum width of the epoxy should be 40mm, that leaves 10mm each side of the rails, cause epoxy rises like 5mm near the edge. I made mine something like 5mm high. Used magnets 4.5mm thick at both corners both sides, to check visually whats going on and make perfect 5mm height


About the laser cut pieces, i dont see why they would charge more for the holes. I ordered mine with holes, that's was the whole point, to save time drilling precisely. Even the 4mm holes were perfect.

Clive_S and Syliavski thanks both for your answers
As for the holes Syliavski there is a limit about the holes that laser can cut in relation to the material thickness.
So at 10mm plate isnt easy to cut 4mm holes. Also the charge at laser cutting is according the time the machine cuts ( this of course is influenced by the length of cut, material thickness and material )

Vagelis

Hi everybody
Today i go on with the gantry
I start by drilling the holes for the bf/bk on y axis. to do this i remove the 120X60X3mm middle tube of the gantry. I put the ballscrew on place and point the holes
Attachment 13094Attachment 13097

Then i put the tube back to the gantry and start aligning the tubes with the steel plates. After that i start spot welding the pieces. With small weld in order not to produce muh heat


Attachment 13096Attachment 13095Attachment 13099
At this photo you can see the 1120mm long m8 bolts that i use to keep in place the side 10mm steel plates
Attachment 13098Attachment 13100

After the side spot welding i had to weld the tubes at their side that atteced each other
First pass i start with spot welding every 10-12 cm. Second pass i weld between the old spot welds ( every 6cm) and so on.... In order to have better result i turn the gantry a bit

Attachment 13102Attachment 13101
Finally i end with this result
Attachment 13103

Attachment 13104Attachment 13105
Then i put the front steel plate on the tubes construction and temporarily i put the rails on, in oredr to see where to drill the holes in order to bolt the plate to the tubes

Attachment 13106Attachment 13107Attachment 13108

The only question i have is about the way i weld the tubes. Are these spot welds ( every 3-4 cm) enough or i should make a full weld

Thanks for your time
Any suggestion will be glad to hear

Vagelis

That with the long screws holding the plate is great idea, thanks for sharing the photos. I will do the same, as i don't have long clamps.

All looks very good!

I fully welded the gantry on the machine i finished and spot welded the Z. Now that you have all in place why don't you repeat the spot welding until all spot welds are very close?
If it was me, i will fully weld it, though it seems that will work both ways. Welding precisely takes a lot of time , i know. I made 5cm stitches, and took care that the temperature of the gantry not to rise above 60 degrees. Used an infrared thermometer. And had to wait a lot for the metal to cool.

You were lucky if your long plate was straight. I had to hammer down to rectify some of the laser cut stuff. Good that i have very big plastic head hammers.

Quote:

---

Originally Posted by silyavski

That with the long screws holding the plate is great idea, thanks for sharing the photos. I will do the same, as i don't have long clamps.

Now that you have all in place why don't you repeat the spot welding until all spot welds are very close?
If it was me, i will fully weld it, though it seems that will work both ways. Welding precisely takes a lot of time , i know. I made 5cm stitches, and took care that the temperature of the gantry not to rise above 60 degrees. Used an infrared thermometer.

---

Syliavski i think ( not sure, that is why i ask ) that i have nothing to add to the stiffness of the machine. One small spot weld is too strong . On the other hand too much heat may cause deflection and twist . Dont forget that my machine is bigger than yours ( y axis is 1160mm long) so it is more possible to have twist issues.

Quote:

---

Originally Posted by silyavski

You were lucky if your long plate was straight. I had to hammer down to rectify some of the laser cut stuff. Good that i have very big plastic head hammers.

---

I think it is not but when i bolt it on the tube construction it will be as straight as the tubes. Even then i am not sure everything will be straight. May be machining or epoxy method will be applyied.
I have a small problem with the resign. The Greek supplyer of West system epoxy doesn have the 209 hardener. On the other hand the 209 hardener is not easy to be shipped as it is described as dangerous to travel . I have to look for another resign

Vagelis

Quote:

---

I have a small problem with the resign. The Greek supplyer of West system epoxy doesn have the 209 hardener. On the other hand the 209 hardener is not easy to be shipped as it is described as dangerous to travel . I have to look for another resign
Vagelis

---

Well check here:- http://www.ebay.co.uk/itm/West-Syste...item1e8ff2bb79 I know this is not a good place to buy it but they do ship to your country . Have you tried to buy it from the UK or perhaps tried a boat yard, also ask them why they can ship the 205 but not the 209. Wests is the best product and it gives you about a 10 hour cure. ..Clive

Apart from stiffness there is dampening of vibrations to consider. Not fully welding may worsen things there. I have never seen commercial mill or cnc spot welded, that should be enough answer for you.

Not every one uses epoxy. I believe it helps dampening. There is German company selling something similar, it was called Moglis, I am not sure. Will search, I had the link somewhere. It's meant to be used for shimming the rails. You can do that with normal epoxy, though the proper one has high compression rating without deformation.
Shimming definitely will be cheaper. But then you will need long straight edge.

Quote:

---

Originally Posted by Clive S

Well check here:- http://www.ebay.co.uk/itm/West-Syste...item1e8ff2bb79 I know this is not a good place to buy it but they do ship to your country . Have you tried to buy it from the UK or perhaps tried a boat yard, also ask them why they can ship the 205 but not the 209. Wests is the best product and it gives you about a 10 hour cure. ..Clive

---

The Greek supplier can ship me the 105 epoxy and the 205-206 hardener but he doesn’t import the 209 hardener.
Other sites even from uk they cant ship (via air) any hardener. Find them

http://www.ecfibreglasssupplies.co.u...acks-12kg.aspx
i think they are cheap at their prices but i emailed them and they answered

"HI Unfortunately we do not stock this product abd cannot ship outside of the Uk due to hazardous content, you may be best to contact west system direct for nearest distributor. Sorry we could not assist with your enquiry . Kind rgds Martin"

As searching i saw that some datasheet measure the viscosity at cps and others at mpa.s. I don’t know what is the difference as when i google search for a converter

http://www.aqua-calc.com/convert/dyn...cond/start/165
i see that they are equal


I found a company CARBON MODS

http://www.carbonmods.co.uk/products...arter-kit.aspx

that sells its products through this site
http://www.easycomposites.co.uk/

At this site
http://www.easycomposites.co.uk/prod...ion-resin.aspx

i found an infusion epoxy resign
here is the datasheet
http://www.easycomposites.co.uk/down...sion-Resin.pdf

From a first reading it seems to have ( according the numbers of the datasheet ) smaller combined viscosity (225 mpa.s) than 105+209 hardener resign (650 cps ) , also it has pot life 80-100 minutes (slow hardener ) smaller than 105+209 (40-50 minutes) , and the price is 18.42+vat pounds.
I don’t know which product is better for our application.


but when i go to the transport details page
http://www.easycomposites.co.uk/dang...-shipping.aspx

Greece is at the red list

Thanks for your participation

This is the stuff I used, worked fine.
http://www.reactiveresins.com/syntac...poxyresins.pdf

Quote:

---

Originally Posted by EddyCurrent

This is the stuff I used, worked fine.
http://www.reactiveresins.com/syntac...poxyresins.pdf

---

Edyy, was it cheaper you said?




Did you checked the link i provided you. For sure they ship, as i have it in my garage :frog:

Here is another link, they ship also PS. deleted the last link, very expensive.

Quote:

---

Originally Posted by ba99297

From a first reading it seems to have ( according the numbers of the datasheet ) smaller combined viscosity (225 mpa.s) than 105+209 hardener resign (650 cps ) , also it has pot life 80-100 minutes (slow hardener ) smaller than 105+209 (40-50 minutes) , and the price is 18.42+vat pounds.
I don’t know which product is better for our application.

---

Its not only that. There are other things important for leveling the rails. The compression yeld, surface quality and precision.

Attachment 13115

I am confused
First of all they dont ship to Greece ( may be to other countries but not to Greece) any epoxy because it is dangerous
The Greek supplyer doesn import the 209 hardener
I find other epoxy systems but every one has different datasheet parameters
For example west system says pot life of 100gr at 22 C, other says pot life 1lt at 25 C. How to compare?
Also it is not clear what everybody mean by saying Pot life, gel time, working time. I call them . One says all the above are the same, other says they are not. I have not a way to compare.
I find one Greek supplyer that has an australian product Megapoxy HX
This product has 60 cps viscocity and working time according the greek site (english version ) datasheet 30 minutes


http://www.megapoxy.gr/index.php?pN=...ProductID=6283
and the datasheet here

http://www.megapoxy.gr/images/pdf/Me...tion_%20En.pdf

and according an australian site (english version ) datasheet

http://www.permatech.com.au/tds/megapoxy_hx_tds.pdf 60 minutes.

What i should believe?

Also its compressive strength is bigger than west system (13778 PSI vs 12000 PSI )
For sure viscocity is very low ( ten times smaller than west system) , but working time also


Thanks for your time

Vagelis

:toot:wait a second! :toot:

I am going to explode from epoxy knowledge these last days :hysterical:

I am right here where you are with my next build . I need epoxy also, so i have done some additional research, locally, i mean. $$$$ i mean versus West System


1. How many L or KG of mix you will need, add 30% at least, for errors or mistake in calculation.

The channel for 20mm rail must be 40mm wide and 5mm thick

Yesteday i read a lot of epoxy material and it seems that the minimum thickness must be 3mm at least -otherwise the forces will not spread. So what we do here at the forum 5mm is ok.

2. lets see what compression strength epoxy we really need.

Heavy duty build, like mine or yours.
2x90mm Hiwin each side, separated at least 90mm each +50mm force spread approximately each side, that 20mm wide= ((2x90+90+2x50)x20)2=14.800 mm2= 148cm2

12800psi to kg/cm2=843kg/cm2 , so we have 148cm2 x 843kg/cm2==124 764 kg . safety factor 125 tons :3= 40 ton gantry , It seems enough, yes?


2. I am at the point of buying epoxy

I found 8kg pack of Spanish epoxy that seems to fit the purpose for 140euro. I need half only. it has only 120kg per cm2 resistance, but even that is more than enough. I can spit it in half if enough for you and ship it to Greece via UPS for 20eur. I spoke personally with the guy that makes the epoxy and he told me it will be perfect for the purpose

I am waiting to speak tomorrow with another company which has very similar epoxy to WS, and slightly cheaper per kg if to buy small packs.

or i could buy more 209 hardener from UK, together with all i need for my build and ship it to you. i can ship up to 30kg for 20eur to you.

So don't waste time with the epoxy, calculate what you need and i will help you.

3. gell time is when the poxy becomes unworkable. Pot life is the same but only if you keep the mix in the pot, where it hardens faster than if spread on the rails. Thats why the confusion. the more epoxy you keep in one pot, the faster it hardens, hence they must state how many g or kg when saying gel time or pot life.

The most important parameter is the viscosity because it need to flow like water to level out and the longer the cure time (wests is 10 - 20 hours) the better as it will have more chance to level out. Also let it cure for at least 5 days. ..Clive

This is what it says about shipping where I got my stuff.
http://www.reactiveresins.com/index.html

"Shipping and handling
Orders over £200 sterling will be delivered free to most of Europe including the following countries Belgium, Denmark, Estonia, Finland, France, Germany, Gibraltar, Greece, Italy, Lithuania, Netherlands, Norway Poland, Portugal, Spain, Sweden, Turkey
We use various couriers in order to get the best combination of service and value for money for our customers."

Now I'm not saying you want £200 worth of epoxy but my point is they will ship it to Greece / Spain all you need do is contact them for a price.

When you click to 'buy on line' it takes you here; http://www.resinstore.com/epoxy-packs.html
The one I used was this, 'Syntac EPAFD Slow Cure Epoxy Resin Pack'

Quote:

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Originally Posted by silyavski

Edyy, was it cheaper you said?

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Yes it was cheaper than West Systems

very interesting book and fast to read. http://nilsmalmgren.com/Laddas/Epoxy_handbook.pdf

from the book:

Attachment 13227

Quote:

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Originally Posted by EddyCurrent

The one I used was this, 'Syntac EPAFD Slow Cure Epoxy Resin Pack'
Yes it was cheaper than West Systems

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But didn't yours Sink Eddy.? . . . . No point being cheap if it's going to compress.!

Quote:

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Originally Posted by JAZZCNC

But didn't yours Sink Eddy.? . . . . No point being cheap if it's going to compress.!

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I agree there completely.

Eddy, just reread your build thread. It seems that what saved you was that you tightened equally the screws. But nevertheless that was a disaster in my opinion. I would have returned the epoxy :hysterical: for complete refund, given that you followed all normal epoxy procedure: weight the mixture to the gram, mix carefully 5 minutes, pour in new container before applying, apply at correct temperature, dry at correct humidity and temperature.
If you remember my thread, the WS epoxy could be filed just next day, though i waited a week. It was like snow flakes with excellent machine ability just next day.

Of course i also made a mistake there. i should have covered the rails below with epoxy base, so it would glue better to the steel. i did not do it and the small pieces at the gantry legs unglued when drilling. I fixed it but still see this as serious mistake from my side.


Just read at Spanish forum that the epoxy i was aiming for did not harden properly when the mix volume was very small - 10g. Thats another good reference if the epoxy is any good or crap... How it behaves when the mixture volume is very small. So its a "no go" for me and i will be ordering the West System today. After spending 5k for my machine i don't see a reason for saving 80euros.