This is my first BUILD please help.

Hi. I am researching this field for months and I decided to make one. I ordered almost all parts except the linear rails. I am going to make them.
I have all the parts but I'll post pictures tomorrow because it is late now to take pictures :fat:. Anyway this is the parts info:

1. 4 x Axis Driver 2M542 4.2A & Breakout interface board for Router system for CNC
2. 2 x ballscrew RM1605-1300mm (for dual X axis)
   
3. 1 x ballscrew RM1605-900mm (for Y axis)
   
4. 1 x ballscrew RM1605-250mm (for Z axis)
   
5. 4 x flexible couplers
   
6. 3 x NEMA23 425 oz-in CNC stepper motor /3.0A (two for X, one for Y)
   
7. 1 x NEMA23 287 oz-in CNC stepper motor (for Z)
   
8. 4 set BK12/BF12 ballscrew end support
9. 12 x SBR20UU BLOCKS
10. 3 x Cable drag chain wire carrier 10*20mm 1000mm (40")

I have all of this parts and I hope I am on the right track, I'll be so frustrated if I made some mistake because my budget IS VERY VERYYYYYY TIGHT.
Anyway I would like a little help.

1. What is the best alu plate thickness I should use for the Z construction and the gantry. I was thinking of using 20mm plates. Is that good?
2. How should I place the linear support rails on the Y axis? Should they be mounted on the front of the alu plate or one at the top and one at the bottom? What is better system?

I have some drawings on paper but still nothing on PC and I am not sure if I make because I am not that good in 3D software.
Please help me with this first questions. THANK YOU

PS: Like I said I'll post pictures tomorrow.

Sketchup is free and really easy to learn, there are some very good tutorials here:

Sketchup for Woodworkers - Home

You can import all the standard things like your ballscrews etc straight into the program so you don't have to worry about trying to draw them.

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Originally Posted by D.C.

Sketchup is free and really easy to learn, there are some very good tutorials here:

Sketchup for Woodworkers - Home

You can import all the standard things like your ballscrews etc straight into the program so you don't have to worry about trying to draw them.

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Yes I know about the sketchup but where can I find the ready-made parts? I really don't have time to design every part and bolt from ground up.

From inside sketchup, goto file import and then search for sbr20 and up pops a linear rail, bearings and mounts component.

If you can't find something inside of sketchup try a google search for 'rm1605 ballscrew sketchup' and download the file onto your computer, then you can import it into sketchup from your computer.

To be honest it seems a little odd to buy all the parts first with no idea about how to arrange them into a working machine and then start trying to figure out how to do it with no money for making mistakes and no time to learn how to do things.

If you take a look at the build logs most people seem to take many months to assemble their first machine, it might be best to put a plan together first either properly done technical drawings on paper or a CAD model that way people here will find it much easier to help you.

I'm just starting to put together a plan for my own first build and from most of the information I've garnered it seems that 20mm plate is fine and the top & bottom rails on the gantry is quite popular.

Try reading this thread, it has CAD drawings and photos to help you visualise:
http://www.mycncuk.com/forums/diy-ma...gn-advice.html

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Originally Posted by D.C.

From inside sketchup, goto file import and then search for sbr20 and up pops a linear rail, bearings and mounts component.

If you can't find something inside of sketchup try a google search for 'rm1605 ballscrew sketchup' and download the file onto your computer, then you can import it into sketchup from your computer.

To be honest it seems a little odd to buy all the parts first with no idea about how to arrange them into a working machine and then start trying to figure out how to do it with no money for making mistakes and no time to learn how to do things.

If you take a look at the build logs most people seem to take many months to assemble their first machine, it might be best to put a plan together first either properly done technical drawings on paper or a CAD model that way people here will find it much easier to help you.

I'm just starting to put together a plan for my own first build and from most of the information I've garnered it seems that 20mm plate is fine and the top & bottom rails on the gantry is quite popular.

Try reading this thread, it has CAD drawings and photos to help you visualise:
http://www.mycncuk.com/forums/diy-ma...gn-advice.html

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I already said that I HAVE the plan in my mind and I have some drawings on the paper but not on a computer. I'll do some sketchup on PC and post it. Anyway, I ordered the parts because I have figured out how the machine will look. I also spend months and months ordering and thinking. It's not like I got up in the morning and ordered some random parts to make myself CNC.
The position of the rails is something that can be changed during the process. It is not something you buy and make mistake.
The rails are the same, but the design is different.

My apologies, I was trying to help not infuriate.

This post has the rails/screw models in if it helps.

http://www.mycncuk.com/forums/cad-ca...html#post35866

The bit I don't get is you've ordered some top quality (read expensive) kit and the SBR20UU blocks yet you are going to make the linear rails. Clearly your working envelope is 1200 x 800 x 150 approx and its hard to see how you'll get the accuracy required over those sort of lengths. What exactly are you planning to do there?

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Originally Posted by D.C.

My apologies, I was trying to help not infuriate.

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The toys did leave the pram PDQ, probably best not to ask how he intends to make the rails :disturbed:

Like DC I am new to this & still planing but he offers some good advice from what I have learnt so far. What materials & components you use will depend on what you intend to cut with the machine. What sort of material will you be cutting as the more experienced members will ask you this.
20mm has been used for a few builds but you need 20mm plate not 20mm flat bar. What else will you be using for the gantry construction other than the aluminium plate?
What experience of machining or what tools you have available will make a difference.

OK thanks to everyone for the answers BTW D.C there is no need for apologies, it is OK :).
I am planning to use the CNC for milling some thin aluminum, then wood, plastic, that kind of materials.
I am forced to make the support for the linear rails because those parts are really heavy and the shipping to my country is $$$.
I have the roods from pro-chrome but I need to make the support rails. Now this is really a problem so that's why I am asking for help.
I was thinking of using two L shaped profiles and one aluminum bar in the middle like sandwich and tight that up with nuts and bolts on every 5cm or so. Like this

_|[]|_

I know it is not perfect solution but what do you think about it? Can you give me another idea of making the support rails?

THANK YOU VERY MUCH for the understanding.

Here are some nice pictures to get started.

Attachment 7163Attachment 7164Attachment 7165Attachment 7166Attachment 7167Attachment 7168Attachment 7169Attachment 7170Attachment 7171Attachment 7172Attachment 7174Attachment 7175Attachment 7176Attachment 7177Attachment 7178Attachment 7179Attachment 7173

Right now I am working in google sketchup and trying to do some design.
Anyway can someone answer me the first question if the rails for Y are better top-bottom or front face.

thanks.

No problem digisoft, just a misunderstanding. :)

Unless you already have access to a workshop you will probably have to rig something up to grind a 45 degree angle in your supports like this guy has done:

Grinding a 45 degree angle for a linear rail with my CNC - YouTube

One problem with this approach is that you have to use v-groove bearings as wheels and the wheels will need frequent adjustment as the rail wears and your wheels become loose. The v-groove bearings are also really expensive and hard to get hold of.
It might be easier to use a piece of box section or square bar at 45 degrees as the rail like this:

/\
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That way you can use skate bearings (just the normal wheel bearings from skateboards) which are really cheap, it wears down slower so it requires less adjustment and it means a lot less work to setup.

OK if I have picked you up correctly you are going to make your own supported rail using the ally profile & chrome bar. First question would be what sort of equipment do you have access to because I would imagine you would really struggle to be able to drill & tap a length or round chromed hardened steel bar with DIY gear unless you already have your own workshop.

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Originally Posted by martin54

OK if I have picked you up correctly you are going to make your own supported rail using the ally profile & chrome bar. First question would be what sort of equipment do you have access to because I would imagine you would really struggle to be able to drill & tap a length or round chromed hardened steel bar with DIY gear unless you already have your own workshop.

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YES YES that is what I am trying to do.
D.C. that is not a solution because I already have the ball bearings.

I have workshop and I have big table drill and other tools. I don't have router and I can't melt aluminum :D
Please help :)

THANKS TO ALL!!!!

I calculated the Z part and ONLY the aluminum 20mm plates will weight 11Kg. It is not included, the rails, sliders, stepper etc etc, only the aluminum plates construction. Is that too much? Should I sue thinner plates?

A typical gantry will weigh in at 20 - 25kg. Without seeing a drawing of how your gantry is designed its impossible to say what the impact of making them thinner will be. Rigidity is key...

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Originally Posted by irving2008

A typical gantry will weigh in at 20 - 25kg. Without seeing a drawing of how your gantry is designed its impossible to say what the impact of making them thinner will be. Rigidity is key...

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Here is some unfinished design.
Please tell me what do you think.

Thanks.

Attachment 7200

Going off advice given to my design, and the veiws i know others share I'd say it seems to have the right things in the right places pretty much.

Critisism: flip the stepper motor and mount it on the back then use a belt and pulley system. This will reduce resonance, as well as other things? (correct me)
Perhaps also mount the ball nut inline with the rails, might help give greater travel in x?

Finally, ignorance is getting the better of me, are you really from chernobyl?

Quote:

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Originally Posted by Hobgoblin

Going off advice given to my design, and the veiws i know others share I'd say it seems to have the right things in the right places pretty much.

Critisism: flip the stepper motor and mount it on the back then use a belt and pulley system. This will reduce resonance, as well as other things? (correct me)
Perhaps also mount the ball nut inline with the rails, might help give greater travel in x?

Finally, ignorance is getting the better of me, are you really from chernobyl?

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Hahahahahahhaa no my friend, I am not from there. I just put it like that :D
Thank you for the help.

Can you tell me if the Y distance of the rails (vertical distance between the Y rails) is better to be 150mm or 200mm. Y will be 1140mm long

PS: I am still working on the Y boll-nut. I just put it like that, it is not in place.
PSS: I was also thinking about belt and pulley for the Z but I don't have those parts and it will complicate my design. What do you think? Is there that much difference?
All aluminum parts are 20mm tick.

I changed the design little so the Y distance between the two axis is 150mm
Attachment 7202

Do you think this is better?

Its always better to have the y-rails as far apart as you can and as low down to the bed as you can to improve torsional stiffness...

I think you could reduce the thickness to 12 or 15mm without undue effect...

What is the box section between the rails? material and dimensions?

Quote:

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Originally Posted by irving2008

Its always better to have the y-rails as far apart as you can and as low down to the bed as you can to improve torsional stiffness...

I think you could reduce the thickness to 12 or 15mm without undue effect...

What is the box section between the rails? material and dimensions?

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This is my newest version. I found that I must put the ballscrew in the sandwich so I can use the maximum length.
The box section of the two pieces that hold the rails is 50mm x 60mm at 4mm thickness?. I am thinking of using stainless still. What do you think. Will they bend?

Attachment 7203

I don't think the backplate on the rear of your z-axis adds a great deal to the performance of the machine, if you get rid of it you can bolt a plate to the back of you gantry to improve stiffness. If that still doesn't provide enough stiffness for what you are using the machine for you can always pour concrete into the box section.

Concrete is obviously heavy but weight can be reduced by adding things like vermiculite/perlite/polystyrene beads etc into the mix to displace the sand and and some fibre glass or fine steel fibres to add reinforcement.

hmm so you say the backplate won't do much think?hmmmm
I am thinking to use 5mm for backplate.

Assuming a typical spindle/z-assembly the 50 x 60 x 4 isnt strong enough for that 1140mm length if its aluminium, the deflection in the middle will be around 0.1 - 0.2mm and torsionally the deflection under cutting loads at the tool tip will be similar, so needs to be steel. You'll still need to join the two box sections with a plate, or a series of plates at the ends and in the middle to transmit torsional forces from one to the other and to maintain the rail seperation accurately else you'll get binding. The other issue is that box section isnt flat enough to mount those rails on unless its ground flat after assembly, you'll not be able to maintain the rail spacing accurately enough to prevent binding. Aluminium extrusion is better but again needs to be bigger, e.g. 100 x 50 for tortional stiffness. 5mm plate is probably too thin, the deflection at full Z extension under cutting load could be ~0.2mm. 15mm plate seems to be the norm, and will limit the deflection to <0.1mm. These calcs are very rough.

Tomorrow I will be cutting the aluminum pieces for the Z gantry.

For now I have two questions.

1. What type of bolts should I use? What is preferred size for bolting 20mm aluminum?
2. There are two screws on the Linear ball sliders. One is on the top in the center and one on the side of it. Why are those used for? I heard for tightening the bearings but why two?

Here is some progress i made so far. Everything is made of steel except the font panel of the Z axis, that is 20mm alu.
Please comment.

Attachment 10155Attachment 10156Attachment 10157Attachment 10158Attachment 10159Attachment 10160Attachment 10161

Attachment 10162Attachment 10163

wow! -- excellent work.

keep the pictures coming

Thank you, I'll make new more quality pictures. These were taken with my phone :)

Looks good, how did you join the side plates to the ends of the big box section ? I can see there are 6 bolts used somehow.

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Originally Posted by EddyCurrent

Looks good, how did you join the side plates to the ends of the big box section ? I can see there are 6 bolts used somehow.

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The big box section (140mm x 60mm x 5mm) has welded 12mm steel plates on the both ends. Then the ends are machined to get 90 degree. I used 6 bolts M8 to bolt the sides.

Quote:

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Originally Posted by DigiSoft

Here is some progress i made so far. Everything is made of steel except the font panel of the Z axis, that is 20mm alu.
Please comment.

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Nice Job and like colour it must be heavy thou with those big lumps of steel what weight is it.?

It is around 100 Kg +-10

Tomorrow I'll make quality pictures and I'll take some pictures of few unmounted new parts.

Quote:

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Originally Posted by DigiSoft

It is around 100 Kg +-10

Tomorrow I'll make quality pictures and I'll take some pictures of few unmounted new parts.

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So with Spindle and other attachments like X ballscrew mounts and cables etc you'll probably be pushing 120Kg+.?? . . .At this weight your going to have to be careful with motor tuning using slaved stepper motors. The inertia of this thing at higher feeds will try pushing like crazy so if your thinking to use machine for router type wood work then you may need to consider servo's.?

You'll certainly need to keep plenty of torque in reserve with slaved stepper motors otherwise your open to racking. What do you plan to use machine for.?

What pitch screws.?

YES YES I will be using slaved steppers for X axis. 1 stepper at each side. I use 425Oz 3A NEMA 23 stepper motors. I bought 42V 750W / 15A PSU. I would like to be able to work on steel too. Do you think it would be possible?

Today I ordered steel working table. They will be making T slots in it. I have access to CNC shop with big cnc 2000mm x 2000mm working table. My table will be 1500 x 900mm and around 200KG.

The gantry complete like you said will be around 120kg.

I use RM1605 (5mm pitch / 16mm diameter).

I do not need fast machine. I just want to be stable and precise.

At lower feeds which you'll run for steel and aluminium you'll be probably be ok but they will struggle with higher feeds or heavy cutting conditions.
Personally I'd be looking into small servo's or at least Nema 34 motors and high voltage drives. Even small 400W servos will be fine has they give linear torque so won't restrict machine potential.

The 3Nm motors and low voltage you plan will be very limiting to machine performance has speed increases.! They should handle lower feeds ok but seems a shame to build what sounds like is going to be a very well built and sturdy machine and not be able to exploit it's full potential.!! . . . . That said they will get you started but think you'll probably quickly want to upgrade.

I have made a big progress with my CNC.
The worktable is finished and the construction is welded. It is night so I couldn't make better picture, but in few days I'll post more work progress. Everything is made of steal. Tubes are 80mm x 80mm x 4mm. The worktable is machined from steal.

Overall weight ~ 500KG


Attachment 11751

That is one hell of a substantial frame and bed, I can see why it weighs 500Kg, great job :applause:, pity the pigeon's have shit all down it though :highly_amused:

ahahahahahah it is not from pigeon. It rolled over on the concrete while we tried to turn it up side down :D

I made a lot of progress.
Here are some pictures, I hope you like it.

Attachment 12069Attachment 12070Attachment 12071Attachment 12072Attachment 12073Attachment 12074Attachment 12075

Tidy job but the gantry and supported rails seem quite a bit less substantial than the base and bed, that's not to say it won't perform well.
Next you will have to skim the bed to make sure it's flat.