[vakeiros]

Well guys, finally got to the building stage, I still have to do the final design (I think I'll do it tomorrow) but I got almost everything figured out so I opened this thread. I'll only receive the ballscrews and linear motion tomorrow so that's when I can make the final design with the exact measures to follow during the construction!
the specs are:

Gantry type, designed to cut wood and aluminum only.
full size: 1300*800*800mm
work area: X 850mm; Y 530mm; Z 180mm
structure materials: Steel and Aluminum
Spindle: Hertz 2,2kw 18k rpm
VFD: Delta VFD 2.2Kw
Steppers: X 2*270OZ Nema 23; Y 270OZ Nema 23; Z 270OZ Nema 23
Drivers: DQ542M
PSU: 2*48V 480W
Linear motion: X&Y HIWIN 20mm; Z HIWIN 15mm
Ballscrews on all axis

Today I've done the bench where the machine will be builded uppon I'll post some pictures at the end. My first question was: "What will I use to build the machine perfectly leveled and squared? for that I have to have a perfectly straight face to build the machine on..." the answer was simple... I needed a table with a stone... So that was my work today. I've a good friend that make stones of all kinds and has the needed machinery to make me one, I asked him for a 1400*90*40mm straight and polished table top and he provide it to me. It's a 100kg hard stone (pics above). Me and my father made the steel structure to suport the stone. All feet have M22 screws for adjusting and leveling perfectly has I'll need. But I have to buy the screws tomorrow... We welded some steel bar on each feet and tapped M22 thread there. Now I'll buy some M22*80 screws and nuts to insert on each feet (the nut will lock the screws after adjustment) and I'll make some nylon caps to insert between the screw head and the floor (tomorrow I'll have some pics).

This project will take a while so I'll post developments when I can.

the stone table top:



stone structure:

here on the top of the feet we can see the welded bar that has the thread to apply the M22 adjusting screw



some of the aluminum for the building:


Tomorrow I'll end the bench and I'll glue the stone to the structure. I'll also try to make the final design of the machine and post it here.

best regards

BTW: sorry the poor quality of the pics but they are from my phone, tomorrow I'll take some with a good digital camera

[vakeiros]

well some more progress today, I'd finished the bench and glued the top stone.

I also received the linear motion from BST Automation in China, great guys to deal with! very professionals, good prices and excelent suport. However I've a question, the HIWIN HGH15CA blocks didn't came with grease nipples shouldn't they come with that? if yes can someone tell me what's the thread of them?
also a nipple was missing from the 8 HGH20CA blocks (only 7 came with the nipple), these have the thread M6x0.75.

well here are some pictures.




leveling adjuster for the table.


table complete


level for precise leveling (0.02mm/m accuracy), at this point the table is not perfectly leveled yet because of 2 things, first it isn't on the final place and second the glue is not dry yet.


linear stuf!

I'm really excited about this project!

best regards

[bobmagnuson]

It doesn't appear that your pictures are showing.

[vakeiros]

on my PC they are showing... I'll check in my laptop...

yes just confirmed, on my laptop there are pics also...

[bobmagnuson]

Hmmm, they show as broken images for me.

[vakeiros]

please check if you can see them here

[bobmagnuson]

Yes, via my phone. I just realized they're being filtered by my employer's firewall! Thanks!

[pippin88]

Check your package carefully, my grease nipples were loose in the package and had stuck to sticky tape in various places. Otherwise contact Fred and he will fix things up.

[vakeiros]

Check your package carefully, my grease nipples were loose in the package and had stuck to sticky tape in various places. Otherwise contact Fred and he will fix things up.

yes I double checked the all package and there's no more grease nipples. I'd already contacted Fred, he's a great guy I'm sure he'll solve this thing in a minute.

best regards

[vakeiros]

Hi guys, last days Have been VERY busy and could not made any progress on the machine but I've been thinking about it A LOT! and I have a question for you guys (well I have more, but this one is really getting me crasy):

is the steel tube (I'll use 80x40x3mm steel tube as base of the machine) flat enough to apply the rails directly on it? or you guys recommend something else about this? I also though in get some precise flat bar (10mm or so) between the tube and the rail but I don't really know about that... what do you guys say?

picture of the base design:


red - steel tube 80*40*3mm
purple - steel tube 60*30*2mm
green - steel corner 50*50*5mm
blue - HIWIN 20mm rails
grey - steel bar 30*10mm (drilled and taped to bolt the HIWIN rail) inside top red tube, not visible on the pic.

after all frames are perfectly leveled and tightened with bolts they will be welded to each other to increase rigidity and as they are stuck with the bolts it will prevent any movement during the welding.

regards

[vakeiros]

here's a pic with the gantry.



a view with PDF 3D here

[Eldon_Joh]

As to the rails being straight enough.. that depends on the stiffness of everything else. I recommend epoxy leveling. Use system three mirror coat, it takes a week to fully harden, and for that reason it will be dead level after the first 24 hours. Make the epoxy dam twice as wide as the rail and make sure there are no pin hole leaks in the duct tape dam. You will have to scrape the meniscus off the epoxy after its cured because surface tension makes it crawl up the duct tape... or just use some epoxy that cures in an hour and pray its flat in that time..


I am not a fan of using a level to check that two rails/beams are parallel.. put an indicator in the middle between the two beams and put a straight edge across the two beams. Mark the location of where the straight edge contacts the beams and the indicator, and rotate the straight edge 90 degrees, ensuring that your straight edge contacts the two beams and the indicator again in the same location (this way, you don't even need a straight edge, a wood board with three dowel pins pressed in it can work. provided the straight edge is held square to the beams, this method of leveling two axis will get you to within the error of the indicator regardless the length of the beams, or the accuracy of the straight edge.

Provided you cap the ends of the steel tubes that the rail is bolted to, and fill the tubes with sand, I think it has adaquate stiffness for what you intend to do.

[vakeiros]

first of all thanks for the answer!

As to the rails being straight enough.. that depends on the stiffness of everything else. I recommend epoxy leveling. Use system three mirror coat, it takes a week to fully harden, and for that reason it will be dead level after the first 24 hours. Make the epoxy dam twice as wide as the rail and make sure there are no pin hole leaks in the duct tape dam. You will have to scrape the meniscus off the epoxy after its cured because surface tension makes it crawl up the duct tape... or just use some epoxy that cures in an hour and pray its flat in that time..

...

so let see if I get this straight.

first to make a dam for the epoxy, I assume I can just put some duct tape around the tube and that will be enough right? as my tube is 40mm wide and my rails are 20mm that will make the twice as wide that you recommend.

now first question (line of questions), where can I get that mirror coat from System Three? I'm from Portugal and I never even heard of that... is it expensive? can I ask if you can buy it and ship it to me?
second, how thick will I need the coat?
third, how will I perfectly level both beams with each other? well i think that is not very important because in the end it's the gantry that have to be parallel to the floor, right?

I am not a fan of using a level to check that two rails/beams are parallel.. put an indicator in the middle between the two beams and put a straight edge across the two beams. Mark the location of where the straight edge contacts the beams and the indicator, and rotate the straight edge 90 degrees, ensuring that your straight edge contacts the two beams and the indicator again in the same location (this way, you don't even need a straight edge, a wood board with three dowel pins pressed in it can work. provided the straight edge is held square to the beams, this method of leveling two axis will get you to within the error of the indicator regardless the length of the beams, or the accuracy of the straight edge.

...

I didn't undertood this part completely, what exactly do you call an indicator? If you don't mind I would appreaciate some pics/drawings explaining this process (my technical english is not very good lol)

...

Provided you cap the ends of the steel tubes that the rail is bolted to, and fill the tubes with sand, I think it has adaquate stiffness for what you intend to do.

yes, this is something that I intended to do! fill the tubes with sand. I was thinking to fill all the red tubes around, you say only the ones where the rails bolt to?

thanks again Eldon_Joh

[Eldon_Joh]

system three mirror coat is a bartop epoxy coating that takes a week to cure and 24 hours to harden, it is not much more expensive than any other epoxy. $120usd a gallon? i haven't checked the prices lately.
if you can't get it, you will need to find the slowest curing epoxy you can find. 2 hours minimum.

both beams need to be parallel, otherwise the gantry must twist as it slides along the rails.

another method to determine if two beams are parallel is to take two thin wires and stretch them with equal weights across the beams forming an X. they should both touch each other in the center between the two beams.

[vakeiros]

system three mirror coat is a bartop epoxy coating that takes a week to cure and 24 hours to harden, it is not much more expensive than any other epoxy. $120usd a gallon? i haven't checked the prices lately.
if you can't get it, you will need to find the slowest curing epoxy you can find. 2 hours minimum.

both beams need to be parallel, otherwise the gantry must twist as it slides along the rails.

another method to determine if two beams are parallel is to take two thin wires and stretch them with equal weights across the beams forming an X. they should both touch each other in the center between the two beams.

Hi Eldon_Joh,

thanks for everything, I'll take a look to what I can find here in the market and let you know. Today I've been in some local stores and nobody had ever heard about epoxy resin... This country is terrible in this type of stuff... anyway, some of them said they'll talk to they dealers and see if they can provide the epoxy resin. I made mysel clear about the cure time, I asked for at least 3-4 hours of handling time and +24h to fully cure

thanks

[vakeiros]

well, I found an epoxy resin close to the SystemThree MirrorCoat, the Smooth-On Tarbender and I'll follow the Eldon_Joh advice on the levelling with the epoxy (I'll need some tips Eldon, I'll be bothering you with PMs XD).

Well have some progress on the last 2 days. I have almost everyting I need to the machine.

some pics of the job I've done:


and a very rough preview of the base structure:


one thing I'm sure. this thing will be HEAVY! before starting the assemble I'll weight every piece to calculate the final weight just for fun XD

hope you're liking the project!

[vakeiros]

hi guys, forgot to add on last post... I've the machine almost ready in design too. I think I only miss the bearing blocks on the ballscrews (the one nexto to the motor, the BK12's). there's some holes missing too and some steel corners on the bottom red tubes. It will be 100% complete on next update.

heres a pic:


and here a 3D pdf

[vakeiros]

well I completelly finished the design and can finally start measuring and marking the drills. These last weeks have been very very busy with my job but I'm expecting they'll calm down on next weeks. I've placed the order on the Smooth-On resin and it will take about 2 weeks to arrive..., until then I hope I have everyhting ready to mount. After I get the resin it will take at least 5 days to fully cure so, in best case scenario I'll only be able to reaaly start mounting things in 3 weeks... until that I hope I have everything ready to mount. Well the only thing I really can show know Is the final design. I think I still have to get some thick steel right angles done to bolt in the gantry (to bolt the uprights to the backplate), I'll try to illustrate what i'm thinking on the sketch when I get the time and see what you guys think. basically I want to add 4 steel corners, 2 on the right and 2 on the left. The left ones, one between the ballscrew and the upper rail and other between the ballscrew and the down rail, The right ones,one each side of the motor.

anyway, here's what I got now:


3d pdf here

[pippin88]

When doing epoxy you must ensure you pour a nice thick coat. Even relatively running epoxies have a lot of surface tension and this will prevent levelling of a thin coat.

I don't know precisely what thickness is needed, but I found out first hand 1-3mm is probably not enough. I'd suggest aiming for 5mm minimum thickness.

Also, I would drill all the mounting holes after doing the epoxy. If you do it before you need to plug the holes, and then you'll get a meniscus around each bolt.
Do your epoxy wider than your actual rails, because there is a significant meniscus. You'll want to remove this with a file, but it would be hard to get it precisely flat, so best not to have rail near the edges of the epoxy.

Use blue painters tape (also called 14 day tape) / masking tape. It sticks ok, but not too strong and won't remove paint etc. It's nice and stiff and gives a nice straight dam.
You must seal the dam, particularly in the corners. Don't use slow curing epoxy for this, because it'll run out and you'll have to wait 24hrs to do your main pour. If you use epoxy that sets in an hour or so, you can do your main pour the same day.
You need a way to remove bubbles - small blow torch or heat gun (not hair dryer, too much air = dust)

[vakeiros]

Hi pippin88, THANKS A LOT for the information post! I was really needing it!

well about the thickness I was aiming for the 3.5-4mm, that's what Eldon_Joh told me but now you're saying me that I'm a bit confuse XD

about the mounting holes. Here's a big problem in my head... I don't really know how well this epoxy thing sticks to the steel and how rigid it will become... so my question is, if I drill the holes after the epoxy will I be able to punch the marks to it? or I'll have to clamp the rail and drill it through the rail? I was really thinking about drill it first, stick some round stickers on the holes and pour the epoxy on the damn thing. after the epoxy cures I would drill the epoxy alone. this holes don't have to be absolutelly precise in my case bacause my rails will bolt to a steel bar that's inside the tubes. I'll bolt the rails with M5 screws and I'm thinking to drill the holes with a 6mm or even 6.5mm drill so I can adjust the rails preciselly where I want. Again I don't know this epoxy stuff but you you guys say: Drill the mount holes after! that's what I'll do!!

now about the dam and sealing the dam... that blue tape I know it, but about sealing it I thought I only needed to make sure that it is well enough and add extra tape on corners, are you saying that I'll need another resin to seal it first?

about the wide of the beams, well my pipes are 40mm wide and the rails are 20mm, I was thinking make the whole pipe surface (40mm x 1330mm).

now other thing, about my gantry, I was thinking to epoxy level those rails to, I mean the surface of those 35mm aluminum blocks. so question: The epoxy will stick to the aluminum? or should I get the pieces together (the spacers bolted on the gantry backplate) and take it to a shop and get the both blocks milled?

another thing will I have to do something special to the steel so the epoxy can stick to it? (apart from a very good clean)

thanks for all