Recommendations for Z Axis?

Hey guys, can someone please tellme some tips about how get an better Z Axis? I will start the build next week, dont know yet if use this chinese rails or wait until my new ordered HGR20 rails.

I think that will be OK the chinese ones because this machine will be used for MDF routing. and maybe made some aluminium pieces for my next build.

Here is my idea of the Z Axis.

Attachment 18914

Material is 10mm steel will try to drill it and bolt it instead welding, but not sure that can make precise drilling, dont have very good drill press.


Its the whole machine
Attachment 18913

Wherever possible keep the cutter tip within the area inside the linear bearings, where that's not possible keep it as close to the area inside the linear bearings as possible.

If you would like near perfect Z axis IMHO some Very important info:

1. As said above keep the bit tip inside the gantry legs bearings step spread, side view

2. Make the design so that the rails are mounted on the moving z plate and the bearing blocks are fixed. Opposite to what you have done, not that what you have done is not valid for small Z travel.

3. Idealy bearing block spread on Z and on the bearings that move the Z left right / X/ will for same squares, or at least same rectangles, and ideally would coincide exactly on top.

4. A must for my designs is that the spindle is mounted so/ 2 brackets/ that it fortifies the front bearing plate in all positions, including fully extended / especially fully extended/

5. Use square supported rails on Z at least, best Z and X at least. Even better on all machine. 20 size.



PS. Square supported rails don't care how they are mounted. Not so with the rails you have chosen. Ideally on gantry top and bottom, left and right on Z. Your drawing uses them in their weakest positions.

I know you asked about Z axis, but I would not use that design for the gantry sides. That I-beam is very weak when used like that and it will just twist the flange for loads in the Y direction.

I would plate over at least one of the sides to create a box section. You could do this by extending the existing end plate on the end of the main beam so it reaches the bottom of the I beam (lower flange) and joining them.

I-beams can be used for the gantry sides but they need to be orientated so that the flanges are pointing up/down (not fore/aft) and the central web runs inside to outside.

So in top view it would look like this:
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Quote:

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Originally Posted by magicniner

Wherever possible keep the cutter tip within the area inside the linear bearings, where that's not possible keep it as close to the area inside the linear bearings as possible.

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Thanks too much! Really dont undestand 100% what it means but im re drawing and will show again in a few hours.

Quote:

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Originally Posted by Boyan Silyavski

If you would like near perfect Z axis IMHO some Very important info:

1. As said above keep the bit tip inside the gantry legs bearings step spread, side view

2. Make the design so that the rails are mounted on the moving z plate and the bearing blocks are fixed. Opposite to what you have done, not that what you have done is not valid for small Z travel.

3. Idealy bearing block spread on Z and on the bearings that move the Z left right / X/ will for same squares, or at least same rectangles, and ideally would coincide exactly on top.

4. A must for my designs is that the spindle is mounted so/ 2 brackets/ that it fortifies the front bearing plate in all positions, including fully extended / especially fully extended/

5. Use square supported rails on Z at least, best Z and X at least. Even better on all machine. 20 size.



PS. Square supported rails don't care how they are mounted. Not so with the rails you have chosen. Ideally on gantry top and bottom, left and right on Z. Your drawing uses them in their weakest positions.

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Working in a new design then! Very thanks for your time and support!

Quote:

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Originally Posted by routercnc

I know you asked about Z axis, but I would not use that design for the gantry sides. That I-beam is very weak when used like that and it will just twist the flange for loads in the Y direction.

I would plate over at least one of the sides to create a box section. You could do this by extending the existing end plate on the end of the main beam so it reaches the bottom of the I beam (lower flange) and joining them.

I-beams can be used for the gantry sides but they need to be orientated so that the flanges are pointing up/down (not fore/aft) and the central web runs inside to outside.

So in top view it would look like this:
|-|

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Yes i was thinking about extend the side of the gantry, but looks like changing the orientation of the I Beam will be an better choice because i can lower the height of the machine!

One more question.

I think that X Axis needs to move a lot of KGs/LBs i have 1150mm length 16mm rails and 1000mm length 20mm rails, and double and single blocks. Using the 20mm and double blocks will be an good upgrade, right? i think that the 16mm will not support very well all the heavy gantry.

Another question...

Is possible to combine double and single block support in the same rail? if use two of the doubles i need to use an base of 220mm to attach the I Bean to the Rail Block, if use an double and a single one, i will need just 180mm

Show a pics to show what i means. (my english is not good)

Attachment 18916Attachment 18917

I've not used 20mm supported rail only 16mm. I don't know what the price difference is but I'd stay with 16mm or upgrade to profile linear rail (Hiwin etc.)

I don't see a technical problem with combining multiple blocks on one rail. Use whatever fits so single and double would be OK. On my new gantry it will have 4 single blocks per side. Spread them out as you have done so they are at the corners with a gap in the middle.

I meant to ask before - your X axis rails don't appear to be supported on anything. I would not rely on the lower flange which comes with the rail to give you the stiffness. It needs to sit onto a continuous box section or similar running the full length. That would also raise your bearings up and make the gantry sides much smaller, therefore making it very much stiffer for not much effort.

Quote:

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Originally Posted by routercnc

I've not used 20mm supported rail only 16mm. I don't know what the price difference is but I'd stay with 16mm or upgrade to profile linear rail (Hiwin etc.)

I don't see a technical problem with combining multiple blocks on one rail. Use whatever fits so single and double would be OK. On my new gantry it will have 4 single blocks per side. Spread them out as you have done so they are at the corners with a gap in the middle.

I meant to ask before - your X axis rails don't appear to be supported on anything. I would not rely on the lower flange which comes with the rail to give you the stiffness. It needs to sit onto a continuous box section or similar running the full length. That would also raise your bearings up and make the gantry sides much smaller, therefore making it very much stiffer for not much effort.

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I have the 20mm ones at home, i already ordered hiwin too, but for other machine, mainly aluminium working. This one will be mainly woodworking/MDF.

Yes, im fixing the X axis too, i think that will use an 50mm tubing but will use epoxy to level up and to add a few mm because the tubing that have just have 3mm wall and think that are not enough to insert the bolts. :/

Im very Happy today! I (think that) have some good idea for my metalworking machine (will start an building log after receive the linear profiles) and found some epoxy supplier in my country.

About Epoxy, think that this specs are enough for the machine?

Hardness Shore : 82 Shore
viscosity 35—50000 mPas

The hiwin rails works ok at top and bottom like the Chinese profiles? I have a new idea about the gantry. Will draw it tonight and will show you guys.

Enviado desde mi ASUS_Z00AD mediante Tapatalk

Well guys, while i wait fedex to give me my rails, i drawing a few options.

Wich think that will be more robust? Option A or B?
Attachment 18929

Quote:

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Originally Posted by samsagaz

Well guys, while i wait fedex to give me my rails, i drawing a few options.

Wich think that will be more robust? Option A or B?
Attachment 18929

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Option A

B looks like it has an unsupported overhang

Quote:

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Originally Posted by routercnc

Option A

B looks like it has an unsupported overhang

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OK thanks!

What about max weight that hiwin HG20 support?

i will use two nema23 steppers (one on each side) because think that the weight will be a little high for just one motor.

will try to use 70V, as i will be using am882 drivers

if weight are too high i think that fixed Gantry will be the solution, but dont know if fixed are better.

Quote:

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Originally Posted by samsagaz

OK thanks!

What about max weight that hiwin HG20 support?

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much more than you could imagine, especially spread between 4 bearings

Quote:

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Originally Posted by samsagaz

i will use two nema23 steppers (one on each side) because think that the weight will be a little high for just one motor.

will try to use 70V, as i will be using am882 drivers

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Dont try, do it. If you gantry weighs more than 70kg you will need servo motors for normal; feeds and speeds.

Quote:

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Originally Posted by samsagaz

if weight are too high i think that fixed Gantry will be the solution, but dont know if fixed are better.

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You have things wrong. Fixed gantry is better not for weight problems but cause the idea what and how to cut is different. Table weight could be bigger than gantry weight



I don't know why are you going backwards with the build. There is enough build information on forum to build a super-duper machine from scratch.

I or C is not stronger than box section, to begin with... I have build uber strong machines from 100x100x4, most people will use 60x60x4. I say ~80x80x3 or 4 is ideal, as it simplifies construction / no diagonal bracing / and is easy to manage at home.

Look my signature build 1. That machine slices through aluminum without a whisper. Plus i have uploaded the plans for free, so you could save yourself a tremendous amount of time, cause all is fully scalable without any modification up to ~ 1200mm wide and 1200mm long. For longer you just have to change the screw with bigger /20/ and if full size just change sides to rotating nuts, which you could see how is done from my project 2 in the signature.

That is a time proven design done with the help of the knowledgable people here, a lot of research and design time. I doubt you could achieve even 1/3rd of that if you continue to buy without draw, think and decide first. Sorry to have to tell you that.
Every small mistake now, translates as days work to fix it later. and money lost, due to buying the improper stuff

Quote:

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Originally Posted by Boyan Silyavski

much more than you could imagine, especially spread between 4 bearings


You have things wrong. Fixed gantry is better not for weight problems but cause the idea what and how to cut is different. Table weight could be bigger than gantry weight



I don't know why are you going backwards with the build. There is enough build information on forum to build a super-duper machine from scratch.

I or C is not stronger than box section, to begin with... I have build uber strong machines from 100x100x4, most people will use 60x60x4. I say ~80x80x3 or 4 is ideal, as it simplifies construction / no diagonal bracing / and is easy to manage at home.

Look my signature build 1. That machine slices through aluminum without a whisper. Plus i have uploaded the plans for free, so you could save yourself a tremendous amount of time, cause all is fully scalable without any modification up to ~ 1200mm wide and 1200mm long. For longer you just have to change the screw with bigger /20/ and if full size just change sides to rotating nuts, which you could see how is done from my project 2 in the signature.

That is a time proven design done with the help of the knowledgable people here, a lot of research and design time. I doubt you could achieve even 1/3rd of that if you continue to buy without draw, think and decide first. Sorry to have to tell you that.
Every small mistake now, translates as days work to fix it later. and money lost, due to buying the improper stuff

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I understand dear Silyavski, i just trying to use materials that can purchase in my country, :/

Using I steel and weld a 10mm plate in one side i will get a box section like you say, but maybe with more weight.

I don t need high speeds, as its just for home projects, i dont need to cut/route fast!

Will check your project #1 again..

Quote:

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Originally Posted by samsagaz

I understand dear Silyavski, i just trying to use materials that can purchase in my country, :/

Using I steel and weld a 10mm plate in one side i will get a box section like you say, but maybe with more weight.

I don t need high speeds, as its just for home projects, i dont need to cut/route fast!

Will check your project #1 again..

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Even so, you should aim at least at ~200 ipm / 5000 mm/min as absolute minimum. I would say you should aim at 10000 mm/min for a "normall" machine.


Not that you will cut at those speeds but machine needs to be "snappy" with good acceleration. Which is sth i believe you have not considered. At the beginning i was also not aware of that fact. Good that people pointed that to me. Otherwise some jobs will take eternity , too much time even for home.

Now having that in mind, do some research about the efficiency of stepper motors, your load, the motors. Under load it will have only a couple of hundred useful RPM. So do your calculations from this.


What size will be your machine???


PS. here is a link to a calculator, have not checked it extensively but seems right http://techref.massmind.org/techref/...r/estimate.htm

Quote:

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Originally Posted by Boyan Silyavski

Even so, you should aim at least at ~200 ipm / 5000 mm/min as absolute minimum. I would say you should aim at 10000 mm/min for a "normall" machine.


Not that you will cut at those speeds but machine needs to be "snappy" with good acceleration. Which is sth i believe you have not considered. At the beginning i was also not aware of that fact. Good that people pointed that to me. Otherwise some jobs will take eternity , too much time even for home.

Now having that in mind, do some research about the efficiency of stepper motors, your load, the motors. Under load it will have only a couple of hundred useful RPM. So do your calculations from this.


What size will be your machine???

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Gracias nuevamente amigo!!!!

Here i attach the sizes of the actual draw

Attachment 18934

(Sorry for my english)

Quote:

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Originally Posted by Boyan Silyavski

I doubt you could achieve even 1/3rd of that if you continue to buy without draw, think and decide first. Sorry to have to tell you that.
Every small mistake now, translates as days work to fix it later. and money lost, due to buying the improper stuff

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Read this several times and digest it very carefully because it's the best advice you have been given so far.!! . . . . . In UK we teach Children the "Green Cross Code" for crossing roads which reads " STOP" "LOOK" "LISTEN" . . . It's time for you to learn the CNC Green cross code to cross road to success..!!

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Originally Posted by JAZZCNC

Read this several times and digest it very carefully because it's the best advice you have been given so far.!! . . . . . In UK we teach Children the "Green Cross Code" for crossing roads which reads " STOP" "LOOK" "LISTEN" . . . It's time for you to learn the CNC Green cross code to cross road to success..!!

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Thanks dude