Thoughts on Sorotec alu-line machine

[NordicCnc]

Hello,

What do you think about the Sorotec ALU-line design? I think it looks pretty good.

Pros: Simple design. Good utilization of work area with the gantry extending all the way out to the sides. This is possible with the y-axis linear rails mounted on the sides. Very sturdy Z-axis.

Cons: Gantry sides may be a weakness of the machine compared to raised gantry design. Only one ballscrew for the Y-axis may lead to twisting when machining far on one or the other side.

Shoot your thoughts! Do you agree with me or not?

Link to their website: https://www.sorotec.de/shop/Portal-M...Heavy-DIY.html

Youtube video 1 (build): https://youtu.be/lHQrTsjQh_o

Youtube video 2 (machining aluminium): https://youtu.be/FWbOGrORIPs

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[JAZZCNC]

It depends on what you want to use the machine for. If it's mostly woodworking with occasional light/Medium aluminum work then this design is more than capable. The only negative being at this size it needs two ball-screws on the Y-axis.

I've built this style of machine for many years and the high gantry sides are not an issue for the type of work described above. This gantry design is stronger than it looks so don't be put off by the high gantry sides. However, if you are wanting to Hogg aluminum away with aggressive cuts and higher feed rates then high sides and gantry sat directly on the rails is a better way to go.

[NordicCnc]

However, if you are wanting to Hogg aluminum away with aggressive cuts and higher feed rates then high sides and gantry sat directly on the rails is a better way to go.

What if you would compare these builds:

1. High sides, Z-axis travel 250mm. Frame made of 80x80 aluminium profiles. Gantry made of 80x160 and sat directly on the rails. Rails top mounted onto the 80x80's.

2. High gantry sides, same Z-axis travel. Gantry sides made of 30mm aluminium tooling plate. Frame made of 80x80 aluminium profiles. Gantry made of 80x160 and mounted to the gantry sides. Y-axis rails side mounted onto the 80x80's.

I understand the high sides build will always be stronger, unless you would make the gantry sides out of something much stiffer than what the frame would be made of.

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[JAZZCNC]

What if you would compare these builds:

1. High sides, Z-axis travel 250mm. Frame made of 80x80 aluminium profiles. Gantry made of 80x160 and sat directly on the rails. Rails top mounted onto the 80x80's.

2. High gantry sides, same Z-axis travel. Gantry sides made of 30mm aluminium tooling plate. Frame made of 80x80 aluminium profiles. Gantry made of 80x160 and mounted to the gantry sides. Y-axis rails side mounted onto the 80x80's.

I understand the high sides build will always be stronger, unless you would make the gantry sides out of something much stiffer than what the frame would be made of.

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Don't know what you want me to say because you already know the answer.? #1 is stronger it's that simple.
However, 250mm is a lot of Z travel so I would ask your self do you really need that much travel as it will weaken the machine if you use a typical Z-axis design. If you don't need 250mm of travel but require the clearance for material then you may be better looking at a design with an adjustable bed so can fit tall material but still have a nice strong Z-axis.

It really does come down to how you want to use the machine and with what materials. If your thinking to cut steels then I would forget both types of moving gantry and build a Fixed gantry machine from stronger materials.

Edit: If you want a design that's in between high Gantry sides and Sat directly on rails then here's one I built. Again this machine is built for working with mostly woods, it's also got a 4th axis which is why the gantry hangs over the side. The profile is 120 x 80 Item Section and the gantry is L shape design.

[NordicCnc]

Don't know what you want me to say because you already know the answer.? #1 is stronger it's that simple.
However, 250mm is a lot of Z travel so I would ask your self do you really need that much travel as it will weaken the machine if you use a typical Z-axis design. If you don't need 250mm of travel but require the clearance for material then you may be better looking at a design with an adjustable bed so can fit tall material but still have a nice strong Z-axis.

The way I plan to solve this is whenever I am machining aluminium / very light steel, I will use a jig that I put on the table, which will then decrease the Z-clearance. This should work the same way as having an adjustable bed.

It really does come down to how you want to use the machine and with what materials. If your thinking to cut steels then I would forget both types of moving gantry and build a Fixed gantry machine from stronger materials.

The requirement is a large work area, so a moving gantry design and making it as good as possible is my goal. This of course means that it wont be as rigid and as effective for aluminium / very light steel. This is a trade-off I need to make, as I don't have the budget or space to build 2 machines right now.

Edit: If you want a design that's in between high Gantry sides and Sat directly on rails then here's one I built. Again this machine is built for working with mostly woods, it's also got a 4th axis which is why the gantry hangs over the side. The profile is 120 x 80 Item Section and the gantry is L shape design.

That is a nice looking machine you've built! Great idea with the 4th axis too.A few questions if you don't mind:

1. How does it perform in aluminium (tool, cut depth, feed rate)?
2. Do you have a build log somewhere?
3. What is the Z-axis clearance and working area?
4. Any reason why you went with L-shape design, instead of using say 90x180 box section profile?
5. Are the surfaces where the rails sit on the X-axis machined or shimmed?
6. What is the reason for having one rail top mounted and the other one front mounted on the X-axis?
7. Are the gantry sides also made of 120x80 profile? How are those mounted to the gantry?
8. The Y-axis rails appears to be top mounted. Why not side mounted?`Is it to make design simpler with the profile gantry sides?

[JAZZCNC]

The way I plan to solve this is whenever I am machining aluminium / very light steel, I will use a jig that I put on the table, which will then decrease the Z-clearance. This should work the same way as having an adjustable bed.

The requirement is a large work area, so a moving gantry design and making it as good as possible is my goal. This of course means that it wont be as rigid and as effective for aluminium / very light steel. This is a trade-off I need to make, as I don't have the budget or space to build 2 machines right now.[/QUOTE]

That's a good solution and one I'd take if building for my self with your requirements.

That is a nice looking machine you've built! Great idea with the 4th axis too.A few questions if you don't mind:

1. How does it perform in aluminium (tool, cut depth, feed rate)?
2. Do you have a build log somewhere?
3. What is the Z-axis clearance and working area?
4. Any reason why you went with L-shape design, instead of using say 90x180 box section profile?
5. Are the surfaces where the rails sit on the X-axis machined or shimmed?
6. What is the reason for having one rail top mounted and the other one front mounted on the X-axis?
7. Are the gantry sides also made of 120x80 profile? How are those mounted to the gantry?
8. The Y-axis rails appears to be top mounted. Why not side mounted?`Is it to make design simpler with the profile gantry sides?

#1 Cannot tell you this because I've never used iit myself, I only built it, and the owner only cuts woods with it as far I know.

#2 No this is a design I build and Sell.

#3 Z-clearance = 250mm Cutting dims Y1300 x X800

#4 Yes it's a much stronger design than a single piece of profile. It's my own design that I've used for years and it's well-proven on lots of machines.

#5 The surfaces are made flat and on the same plane by coating with a fine spread of Epoxy metal (not epoxy resin) and then machine frame is turned upside down and placed on precision Granite surface table.

#6 The fronted mounted rail is to give maximum clearance under the gantry and the top-mounted rail is to give greater spacing between rails and support the Z-axis rear plate.

#7 Yes 120x80. They are mounted by bolting into the lower flat profile from the top. The top profile is bolted to the flat profile from the underside, there are also aluminum keys inserted into the slots to stop any movement.

#8 It's difficult to align the rails parallel to each other when side-mounted. It's also much more difficult in regards to them being on perfectly horizontal and vertical planes. If the surface the rails mount on is not perfectly vertical then the gantry sides will form a V if viewed from front plane, likewise, if the surfaces are not parallel to each other they will form a V if viewed from Top plane.

[NordicCnc]

I have taken some inspiration from the gantry design in your machine. What I've done differently is:

• It is far from done and many details are still missing. One gantry side is still missing completely.
  
• Y-axis linear rails are side mounted to the 160x80 item profile. This allows a larger work area and the ball screws can be mounted to the same piece of aluminium plate, with a little bit of machining.
  
• Gantry side plate is on the inside and an 80x80 item profile is mounted on the outside of the plate. The 80x80 item profile is mounted to the X-axis 200x80 item profile with a back plate and a bottom plate.
  
• The X-axis ball screw and linear rails are all on the front side. With some machining on of the aluminium plates, I am able to squeeze everything in the with custom made ball screw nut brackets.
  
• The Z-axis is made stiffer with side plates bolted onto the same plate to which the linear rails and ball screw is bolted.
  

Please let me know what you think! Are there any significant improvements I could do to make it better?

[JAZZCNC]

The main issue I see is the Z-axis and the unnecessary weight of it.!

You don't need or want the motor and ball-screw on the front plate because you are just moving around dead weight which will affect the z-axis negatively due to high inertia. Those 180W servos won't handle that weight, especially if your planning on using a large spindle or ATC spindle. You will also need a brake to stop it dropping when unpowered.

Ideally, you want a light but strong front plate with no excess baggage to affect inertia. The ball-screw could easily go on the rear plate and be shorter, the motor could mount to plate coming off slightly longer rear plate. This longer rear plate will also allow more spacing of the bearings which will stiffen things up a little.

The other thing I don't like is the ball-screw on the front. If it was me I'd mount it at the rear out fo the way of chips etc and have the ball-nut mount to the plate which the Z-axis motor mounts onto. Don't worry about the ball-nut not being in the so-called theoretical ideal central sweet spot of the front plate because in real-world the difference isn't noticeable. However, weight in the wrong place very much does affect the machine.

[Kitwn]

Don't forget that if you need a longer tool it's because you're cutting into a deeper piece of material which means you have to lift the tip of the tool that much further above the workpiece. An extra 20mm needed on the tool length implies a possible extra 40mm of Z-axis lift to start the cut.

[NordicCnc]

Cannot comment on the JMC servo's as I've never used them but power is power and 180W isn't massive so you'll have to be mindful of the weight and mass your moving around.
The budget is healthy though so definaltely possible to build a very nice machine.




Well if that's your main reason then it's the wrong way to think because while Aluminium is lighter than steel the total weight of machine this size will still be heavier than 1 or 2 men can handle safely so you'll still possibly need some lifting equipment. So why not just build the best machine you can and don't worry about the weight too much.



Again I wouldn't let this dictate the design of this machine because a VMC worth the effort requires building from steel and this machine won't machine steel to any great accuracy.

If it was me I'd look more along the lines of using this to make money and learn CNC then buy a used VMC that you can retrofit with new components. Or buy old Iron manual Mill and retrofit it to CNC. Both these options will be much better and far easier done than trying to build a VMC with a Router, no matter how well built it is.!




Yes BST is a great place to buy from. Fred is the most helpful and trustworthy Guy I've ever dealt with and I highly recommend him.
Send him a message with your requirements asking for a quote including shipping and he'll get back to you quickly with a price. Mention Dean from Uk sent you and it may help with the price.

Anyway I managed to find a similar machine to yours (please no offence, it is most likely not better or even comparable): http://www.cncrouterparts.com/pro484...kit-p-251.html

What do you think about this one? Can you see any glaring issues?