Choosing aluminium profiles

[NordicCnc]

Hello everyone. I am new to this forum but I have built a CNC mil before and also converted a manual lathe to CNC, so the subject of DIY CNC is familiar to me. The CNC mill was built with 50x50x3 steel profiles and was welded mostly. The linear rails were also the bad version and not Hiwin rails. The spindle motor is a HF 1.5kW water cooled.

I have now started designing a new build. It will be a moving gantry build that I want to be able to machine aluminium with, and steel if possible. I intend to use following components for the build:

2.2kW HF spindle, water cooled
Nema 23 servomotors, brand JMC iHSV57-30-18-36, 2x on Y-axis, 1x on X-axis and 1x on Z axis.
20mm Hiwin linear rails, 2x on Y-axis (1000mm), 2x on X-axis (800mm) and 2x on Z-axis (400mm)
1610 ball screws, 2x on Y-axis (1000mm), 2x on X-axis (800mm) and 1x on Z-axis (400mm).


The frame I have decided to build with aluminium profiles. In my country there is a company called Movetec, selling aluminium profiles (MiniTec Profile Systems). They have 45 series profiles which I am interested in but they are rather expensive, compared to 40 series profiles from Ebay Germany. The 45 series profiles looks very robust and they are also offering fastening solution called MiniTec Power-lock. This solution requires zero drilling/preparation of the profiles. This is the reason why am I am having a hard time deciding which profiles to go for, since they do not offer this fastening solutions for 40 series profiles. The cross sections of each profile can be seen in the attached pictures.

MiniTec Prices:

90 x 90 S: 110$/meter (MiniTec)
90 x 180 S: 200$/meter (MiniTec)
MiniTec Power-Lock: 5$/qty
90 x 90 L: Did not ask the price for these but I can imagine I could save a few $ compared to 90 x 90 S.


Ebay Germany Prices:

80 x 80 L: 50$/meter (Ebay Germany)
80 x 160 L: 100$/meter (Ebay Germany)
Fastener for 40 series: 5$/qty (Ebay Germany)


What do you guys think? Is it overkill to go with the 45 series profiles only because of the fastening solution? Are those profiles significantly better than 40 series profiles? Also advice on component selection is very welcome. I can provide picture of the 3D design (done in Siemens NX) later this week.

There is also a poll for 40 series and 45 series for you to cast a vote on!

Best regards,
NordicCNC

[Voicecoil]

In the final analysis, rigidity is the most important thing, so check the figures for the moments of inertia (Ix, Iy) for the different profiles before making your choice. There are also other vendors/manufacturers such as Motedis, Item, Maunsystem, Misumi and KJN in the UK.

[Gary]

As well as Kanya.
Kanya is not the cheapest, but is the best in the marketplace, with a very wide range of extrusions and excessories.
Also there is extrusions that are heavy duty as well as the light so if you need more rigidity, use the heavy versions.
We sell Kanya by the way. ;0)
https://www.zappautomation.co.uk/mechanical-products/kanya-aluminium-extrusions-236.html

We also have some Isel extrusion thats on sale as well.

https://www.zappautomation.co.uk/stock-sales/aluminium-extrusions.html






In the final analysis, rigidity is the most important thing, so check the figures for the moments of inertia (Ix, Iy) for the different profiles before making your choice. There are also other vendors/manufacturers such as Motedis, Item, Maunsystem, Misumi and KJN in the UK.

[NordicCnc]

As well as Kanya.
Kanya is not the cheapest, but is the best in the marketplace, with a very wide range of extrusions and excessories.
Also there is extrusions that are heavy duty as well as the light so if you need more rigidity, use the heavy versions.
We sell Kanya by the way. ;0)
https://www.zappautomation.co.uk/mechanical-products/kanya-aluminium-extrusions-236.html

We also have some Isel extrusion thats on sale as well.

https://www.zappautomation.co.uk/stock-sales/aluminium-extrusions.html

I had not heard about Kanya! What makes you say those are the best in the marketplace? Do you ship to Finland? Do you have similar fastener solution as the MiniTec Power-lock fastener available?

[NordicCnc]

In the final analysis, rigidity is the most important thing, so check the figures for the moments of inertia (Ix, Iy) for the different profiles before making your choice. There are also other vendors/manufacturers such as Motedis, Item, Maunsystem, Misumi and KJN in the UK.

Thanks for you answer. I checked the moment of inertia and there is indeed a big difference between the 45 series and the 40 series profiles. The 45 series is way more rigid. Since the rigidity of the base is the most important thing, maybe it is a good decision to spend a bit more on the better profiles?

[Gary]

One of the first to bring to the market this type of products, swiss-made, and a very large range. yes there are a very large range of connectors, and you will see them in this link.
https://www.zappautomation.co.uk/mechanical-products/kanya-aluminium-extrusions-236/accessories-241/kanya-connectors-242.html
yes we ship worldwide, and the website should work out the shipping costs, but if not, just email me directly.

[NordicCnc]

These connectors requires machining right? Do you also offer premachined profiles?

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[Gary]

you need to only drill a hole a specific distance from the end. if you need us to do this we can do this for a cost, but i will need to know how many.
But it is quite simple to do.
We normally use an end mill to get a flat base to the hole.

[Voicecoil]

Thanks for you answer. I checked the moment of inertia and there is indeed a big difference between the 45 series and the 40 series profiles. The 45 series is way more rigid. Since the rigidity of the base is the most important thing, maybe it is a good decision to spend a bit more on the better profiles?

Absolutely. As aluminium isn't as stiff as steel you need to get clever and use extrusions that make the best use of the material to get a rigid frame.

[NordicCnc]

Absolutely. As aluminium isn't as stiff as steel you need to get clever and use extrusions that make the best use of the material to get a rigid frame.

Thanks for your help! I will go with the larger/stiffer aluminium extrusions.

[NordicCnc]

you need to only drill a hole a specific distance from the end. if you need us to do this we can do this for a cost, but i will need to know how many.
But it is quite simple to do.
We normally use an end mill to get a flat base to the hole.

I see, thanks for the information.

By the way, do you also offer HIWIN linear rails and HIWIN ball screws or some brand that is of equivalent quality or better?

[Boyan Silyavski]

IMO best is to use Rectangular profiles and design carefully the machine. They cost half as the Square and even in design are more useful to form the structure.

When i see a machine made from square profiles or it looks overbuild and ugly, or underbuild. I would concentrate on each part to be made from the perfect profile for the job, not trying to do all from one profile.

[NordicCnc]

Yes I plan to use 90x90 for the base and Y-axis. For the X-axis I will use 90x180 and for the Z-axis there will be machined aluminium plates. Is this what you meant?

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[Boyan Silyavski]

Yes,

I like overbuild, but isn't that a bit too much for 1000mm machine?

If you have experience with welding why don't you make the machine from 100x100x3 profile steel and use aluminum for the gantry and Z only?? And maybe for the YA if you prefer and all esle from steel


I don't like the type of connection you are showing. For me best is or plate or angle. And now angles are so cheap, i would use only angles and a couple of plates.

[Gary]

We do PMI, TBI and Gten.
Gten is our old range and we are discontinuing nad replacing with PMI and TBI
Gten is on sale at the moment.

I see, thanks for the information.

By the way, do you also offer HIWIN linear rails and HIWIN ball screws or some brand that is of equivalent quality or better?

[NordicCnc]

Yes,

I like overbuild, but isn't that a bit too much for 1000mm machine?

If you have experience with welding why don't you make the machine from 100x100x3 profile steel and use aluminum for the gantry and Z only?? And maybe for the YA if you prefer and all esle from steel


I don't like the type of connection you are showing. For me best is or plate or angle. And now angles are so cheap, i would use only angles and a couple of plates.

My machine that I currently have is 1000mm long as well. That one is buily from steel, welded 50x50x3. I will probably not be able to mill the surfaces of my new machine with my existing one, since it is not rigid enough for effective steel milling.

As for the connections, those are really strong and requires absolutely 0 machining, which is why I like them. What is it about them that you dont like? How accurate are angles and where can I get those cheap?

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[Boyan Silyavski]

My machine that I currently have is 1000mm long as well. That one is buily from steel, welded 50x50x3. I will probably not be able to mill the surfaces of my new machine with my existing one, since it is not rigid enough for effective steel milling.

As for the connections, those are really strong and requires absolutely 0 machining, which is why I like them. What is it about them that you dont like? How accurate are angles and where can I get those cheap?

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I buy angles, plates and profiles from Motedis, bolts and nuts 100% from China, sometimes angles and plates from China too. there is another supplier from Germany that can ship long profiles and screws

You can weld the base and epoxy level it, or shim directly the rails or use smaller and cheaper aluminum profile on top / AY/ and shim profile, all rest from aluminum

Aluminum profile may be perfectly straight or maybe not, whatever the case for a properly made machine you will need a straight edge as long as your X/gantry and at least 2 precision squares. there is no way one to make a good machine without that.

[NordicCnc]

I buy angles, plates and profiles from Motedis, bolts and nuts 100% from China, sometimes angles and plates from China too. there is another supplier from Germany that can ship long profiles and screws

You can weld the base and epoxy level it, or shim directly the rails or use smaller and cheaper aluminum profile on top / AY/ and shim profile, all rest from aluminum

Aluminum profile may be perfectly straight or maybe not, whatever the case for a properly made machine you will need a straight edge as long as your X/gantry and at least 2 precision squares. there is no way one to make a good machine without that.

If I weld the base, wont I have to stress relief it then? Or would it be enough to weld and just use epoxy right after for leveling?

[Boyan Silyavski]

If I weld the base, wont I have to stress relief it then? Or would it be enough to weld and just use epoxy right after for leveling?

Using 100x100 profile or any = no problem. But the key is in the welding. Welding no more than 2 inch at a time from different sides and checking with laser thermometer for the temperature of the beam overall not to rise more than 60 degree C will do the trick. It must be done with patience and cleverness.

If you read my building log you will see that it took me some time to weld my big machine, but it was worth it.

And as i said many times before, 100x100x3 is the ideal material for big strong CNC.

[NordicCnc]

Using 100x100 profile or any = no problem. But the key is in the welding. Welding no more than 2 inch at a time from different sides and checking with laser thermometer for the temperature of the beam overall not to rise more than 60 degree C will do the trick. It must be done with patience and cleverness.

If you read my building log you will see that it took me some time to weld my big machine, but it was worth it.

And as i said many times before, 100x100x3 is the ideal material for big strong CNC.

I did not check but I guess the moment of inertia will be higher for the steel 100x100x3 compared to aluminium extrusion 90x90, even thought 90x90 has a larger cross-sectional area?

What about skipping the welding and bolting the steel frame together with angular plates or plates? That would also make it possible to disassemble the machine if you need to move it around (hopefully not) at some point.

What kind of epoxi should be used for the leveling? I have never done that before. By the way, thanks for all the answers!

[ericks]

I used heavy duty item 24 profile, very good quality product:)

[Boyan Silyavski]

I did not check but I guess the moment of inertia will be higher for the steel 100x100x3 compared to aluminium extrusion 90x90, even thought 90x90 has a larger cross-sectional area?

What about skipping the welding and bolting the steel frame together with angular plates or plates? That would also make it possible to disassemble the machine if you need to move it around (hopefully not) at some point.

What kind of epoxi should be used for the leveling? I have never done that before. By the way, thanks for all the answers!

There are many topics on epoxy on this forum. Somewhere on my second build i have explained very profoundly my experience. Westsystem epoxy, slow cure.

90x90 aluminum i think was same as 100x100x3 or 4mm steel. So no worry. But if steel weld it, if aluminum, bolt it.

At the end time and money spend is same, but if you have more time than money =steel, if you have more money than time=aluminum. Thats the truth for me.