Aluminium Profile Type Router - Initial questions

[JAZZCNC]

Hi Ryan,

Let me just say from the start that the Heavy Mill 3DTEK as got some serious issues and it's far from its name suggests.

First off scrap the Z-axis altogether it's load of rubbish and far too flimsy. The Z-axis is THE most important part of the machine because it's where all the action happens. If it's weak then it doesn't matter if the rest of the machine is built like a tank your cutting will always suffer.
Also, no point using Hi-win profiled linear rails on other axis if going to use a round rail on Z-axis, use either all-round or all profiled. You are wasting your money mixing them.

Next is the Gantry sides, they are also weak and flimsy. They will resonate and flex which again transfers into the cut. To be honest the whole gantry is on the weak side and could easily be made stronger with a design change. Even the Light profile will work if you used an L shaped design.

Regards the ball-screws you will be better with 16mm x 10mm pitch for a wood router at this size. 10mm pitch will easily allow you to cut aluminum without any problems. Whereas 5mm would be too slow for cutting wood correctly.
You don't need 20mm for a machine this size and it will only rob you of power and speed because of the extra inertia of the ball-screw. It takes more power to accelerate and deaccelerate than 16mm and it does make a big difference to performance.

Regards the electrics and controller then always go with Ethernet if you can afford the extra, it's much more stable than USB or parallel port.

Andy mentions Voltage isn't so important but I'm afraid he's wrong, It's very important to the speed and torque you'll get from a stepper motor. The torque you get from a motor is proportional to voltage so if you increase the voltage the torque will also rise, up to a point. To get high speeds from a stepper you need voltage which is why we try to use higher voltage drives so we can boost voltage. Obviously there is a limit dependant on motor/drive specs etc but in general, more volts = higher rpm which is better for a router.

Regards the Motor, drives and PSU spec then there is a well-proven spec for machines this size which has been used for a long time on this forum. Which I'm happy to help you with. However, I'd also advise you to consider looking at Closed-loop steppers as they have come down in price quite a lot and are much better than the standard stepper systems. This could change things a little regards PSU etc depending on which you go for. So go have a look at them if you haven't already and let us know your thinking.?

BIGGEST ADVISE is don't buy anything else until your 100% sure it's correct. Also don't buy electrics until needed as your wasting warranty and things change fast these days regards controllers/software and drives you could end up with a better system by waiting until needed.

Don't be afraid to ask questions no matter how dumb you may think they sound.

[CNCRY]

Hi Ryan,

Let me just say from the start that the Heavy Mill 3DTEK as got some serious issues and it's far from its name suggests.

First off scrap the Z-axis altogether it's load of rubbish and far too flimsy. The Z-axis is THE most important part of the machine because it's where all the action happens. If it's weak then it doesn't matter if the rest of the machine is built like a tank your cutting will always suffer.
Also, no point using Hi-win profiled linear rails on other axis if going to use a round rail on Z-axis, use either all-round or all profiled. You are wasting your money mixing them.

Next is the Gantry sides, they are also weak and flimsy. They will resonate and flex which again transfers into the cut. To be honest the whole gantry is on the weak side and could easily be made stronger with a design change. Even the Light profile will work if you used an L shaped design.

Regards the ball-screws you will be better with 16mm x 10mm pitch for a wood router at this size. 10mm pitch will easily allow you to cut aluminum without any problems. Whereas 5mm would be too slow for cutting wood correctly.
You don't need 20mm for a machine this size and it will only rob you of power and speed because of the extra inertia of the ball-screw. It takes more power to accelerate and deaccelerate than 16mm and it does make a big difference to performance.

Regards the electrics and controller then always go with Ethernet if you can afford the extra, it's much more stable than USB or parallel port.

Andy mentions Voltage isn't so important but I'm afraid he's wrong, It's very important to the speed and torque you'll get from a stepper motor. The torque you get from a motor is proportional to voltage so if you increase the voltage the torque will also rise, up to a point. To get high speeds from a stepper you need voltage which is why we try to use higher voltage drives so we can boost voltage. Obviously there is a limit dependant on motor/drive specs etc but in general, more volts = higher rpm which is better for a router.

Regards the Motor, drives and PSU spec then there is a well-proven spec for machines this size which has been used for a long time on this forum. Which I'm happy to help you with. However, I'd also advise you to consider looking at Closed-loop steppers as they have come down in price quite a lot and are much better than the standard stepper systems. This could change things a little regards PSU etc depending on which you go for. So go have a look at them if you haven't already and let us know your thinking.?

BIGGEST ADVISE is don't buy anything else until your 100% sure it's correct. Also don't buy electrics until needed as your wasting warranty and things change fast these days regards controllers/software and drives you could end up with a better system by waiting until needed.

Don't be afraid to ask questions no matter how dumb you may think they sound.

Appreciate the advice JazzCNC
Heavy Mill was my initial idea as I could see how it was constructed, plus I assumed must be a sufficiently good design to sell:) I'll not be copying it's Z axis in that case, and will design on the same rail setup instead. As I just mentioned in reply to Andy - im's trying to establish some "fixed" ideas and design around that, but X changes so does Y!
So one thing I did notice on heavy mill were weak side's so my design there is similar to Andys log = http://www.mycncuk.com/attachment.ph...3&d=1573338796 . That is rails on top on the extrusion, then a carriage and aluminium block which the gantry rail site on top of,and fixed using side plates .

I'll be looking into 1610 ballscrew based on both the replys now.
Do closed loop steppers work with standard nema motors ? I'll take a look.

I'll be trying to draw this in a shareable format soon. But design steps wise, can I design/build the X/Y axis and gantry to a good standard, then consider the Z axis as the next "module" or is that a bad idea!
If I know the motors to be used, I can pretty much leave electronics until the build progresses, and certainly won't buy anything related to that yet.
Will my existing 120 x 40 profile with 40x40 cross pieces suffice for X/Y axis with extra bracing?
And with the L design for gantry - just thinking how I can incorporate the 90x90 profile, perhaps a 60x60 attached to it at the back?

Ryan

[JAZZCNC]

So one thing I did notice on heavy mill were weak side's so my design there is similar to Andys log = http://www.mycncuk.com/attachment.ph...3&d=1573338796 . That is rails on top on the extrusion, then a carriage and aluminum block which the gantry rail site on top of,and fixed using side plates .

Yes, this is the L design I was suggesting, most of the L designs you'll see are based off my original design or someone else's who took from mine, it can be used both with or without Gantry sides and makes for a very stiff gantry with easy rail mounting etc. When mounting directly to the bearings just bear in mind access to the bearings bolts when deciding the bearing plate length. I've seen several designs that missed this little detail, which is why it's a good idea to draw it in cad to catch these things.

Do closed loop steppers work with standard nema motors ? I'll take a look.

No closed loop steppers have an encoder on the back which goes to the matching drives. Also often closed loop steppers are 3 phase steppers with smaller step angle of 0.9 or 1.2 deg whereas typical stepper is 2 phase. with 1,8deg step. The difference being closed-loop are smoother.

I'll be trying to draw this in a shareable format soon. But design steps wise, can I design/build the X/Y axis and gantry to a good standard, then consider the Z axis as the next "module" or is that a bad idea!

Yes you can but I wouldn't recommended it because your better designing the whole thing in CAD to see if anything clashes.

If I know the motors to be used, I can pretty much leave electronics until the build progresses, and certainly won't buy anything related to that yet.

All you really need to know is the motor frame size ie: NEMA 23 or 34. Now I've seen you mention Nema 34 is what you need.! This would be bad for a machine this size and mistake often made by new builders are thinking bigger is better, it's not.!
NEMA 34 motors require a much higher voltage to get the RPM needed for a router. A 4Nm NEMA 23 will perform much better than a 4Nm Nema 34 at the same voltage.

Will my existing 120 x 40 profile with 40x40 cross pieces suffice for X/Y axis with extra bracing?
And with the L design for gantry - just thinking how I can incorporate the 90x90 profile, perhaps a 60x60 attached to it at the back?

Yes, the 120x40 and 40x40 could be used for the frame with bracing.
Regards the Gantry then Bolting 60x60 onto the back won't do anything other than add weight. To get the stiffness and height you need one piece flat with the other bolted on top. So either buy a wider piece for the bottom and put the 90x90 on top or start again with 2 x 45 x 90.
I'm assuming that your using BR range profile because of the 90mm. This is good because when using 16mm screws then the BK End bearings mounting holes will line up with the 45mm slot spacing. If you used the IR with 40mm slot spacing then you would have to make plates or drill the profiles to bolt the bearings on.

It's these little things that catch you out and cause more work. Hence why drawing in CAD can save many wasted days and money.

[CNCRY]

Yes, this is the L design I was suggesting, most of the L designs you'll see are based off my original design or someone else's who took from mine, it can be used both with or without Gantry sides and makes for a very stiff gantry with easy rail mounting etc. When mounting directly to the bearings just bear in mind access to the bearings bolts when deciding the bearing plate length. I've seen several designs that missed this little detail, which is why it's a good idea to draw it in cad to catch these things.



No closed loop steppers have an encoder on the back which goes to the matching drives. Also often closed loop steppers are 3 phase steppers with smaller step angle of 0.9 or 1.2 deg whereas typical stepper is 2 phase. with 1,8deg step. The difference being closed-loop are smoother.



Yes you can but I wouldn't recommended it because your better designing the whole thing in CAD to see if anything clashes.



All you really need to know is the motor frame size ie: NEMA 23 or 34. Now I've seen you mention Nema 34 is what you need.! This would be bad for a machine this size and mistake often made by new builders are thinking bigger is better, it's not.!
NEMA 34 motors require a much higher voltage to get the RPM needed for a router. A 4Nm NEMA 23 will perform much better than a 4Nm Nema 34 at the same voltage.




Yes, the 120x40 and 40x40 could be used for the frame with bracing.
Regards the Gantry then Bolting 60x60 onto the back won't do anything other than add weight. To get the stiffness and height you need one piece flat with the other bolted on top. So either buy a wider piece for the bottom and put the 90x90 on top or start again with 2 x 45 x 90.
I'm assuming that your using BR range profile because of the 90mm. This is good because when using 16mm screws then the BK End bearings mounting holes will line up with the 45mm slot spacing. If you used the IR with 40mm slot spacing then you would have to make plates or drill the profiles to bolt the bearings on.

It's these little things that catch you out and cause more work. Hence why drawing in CAD can save many wasted days and money.

Thanks Jazz - going to spend the next week or so learning fusion 360 and actually drawing the thing:) Probably makes sense to learn to use CAD alongside building a CNC machine!
The Nema motor - that was me being a muppet. I do mean Nema 23 4NM.
I guess the hybrid steppers are perhaps £50 more each with a driver package then a normal stepper and decent driver, something like https://www.cnc4you.co.uk/Stepper-Mo...-Servo-Kit-4Nm. ?

RE: the profile, I spent a fair amount so far so would really want to avoid wasting . You are right its the BR as below with 45mm spacing, so will make mounting easier.



So do you mean
40x120L along the bottom with 90x90 on top. Notice the slot spacing on that is 40 so no way to direct join - but I guess joining plates at ends will do?



for BST automation shop, which as mentioned is probably not sending anything right now - something like
3 X Anti Backlash Ballscrew RM1610 -L1000mm with SFU1610 Ballnut + BK12 BF12 Support Unit + 1610 Nut Bracket + 6.35*10mm coupler shows as $141 + $107 shipping. $248 total. I've never order anything over a few £ from china - what import duty do people get hit with? Looks like VAT+2.5%?

Ryan

[AndyUK]

For BST automation shop, which as mentioned is probably not sending anything right now - something like
3 X Anti Backlash Ballscrew RM1610 -L1000mm with SFU1610 Ballnut + BK12 BF12 Support Unit + 1610 Nut Bracket + 6.35*10mm coupler shows as $141 + $107 shipping. $248 total. I've never order anything over a few £ from china - what import duty do people get hit with? Looks like VAT+2.5%?

When you're ready, email them for a quote with exact sizes.

I was also concerned about ordering from BST initially, but there are a lot of examples of people here using them. Jazz probably keeps them in business singlehandedly. You can pay with PayPal via AliExpress. AliExpress hold the PayPal payment in escrow until the package arrives and then you release it to the seller. You're also doubley protected by PayPal, and even further if you use a credit card, so it's really no risk at all.

I paid roughly £1100 delivered including all import duty for four ballscrews (30cm 1605, 1m 1610 and two 1m 2010s) with associated ballnuts, ballnut mounts, BK and BF bearings (upgraded to AC I think), all custom machined to my exact lengths and to allow pulleys, all of my hiwin 20mm linear rail (2x1.2m, 2x1m and 2x35cm) and 12 hiwin carriages, and a 2.2kW spindle plus VFD with collets and water pump and spindle mount.

Sounds like a lot of money, but those three things were the most expensive components and about 1/3rd of the total build cost.

I won't go into further detail about the import duty, but trust me don't be concerned. You'll get a text or email when the parcel arrives in the UK and you just pay online.

[CNCRY]

When you're ready, email them for a quote with exact sizes.

I was also concerned about ordering from BST initially, but there are a lot of examples of people here using them. Jazz probably keeps them in business singlehandedly. You can pay with PayPal via AliExpress. AliExpress hold the PayPal payment in escrow until the package arrives and then you release it to the seller. You're also doubley protected by PayPal, and even further if you use a credit card, so it's really no risk at all.

I paid roughly £1100 delivered including all import duty for four ballscrews (30cm 1605, 1m 1610 and two 1m 2010s) with associated ballnuts, ballnut mounts, BK and BF bearings (upgraded to AC I think), all custom machined to my exact lengths and to allow pulleys, all of my hiwin 20mm linear rail (2x1.2m, 2x1m and 2x35cm) and 12 hiwin carriages, and a 2.2kW spindle plus VFD with collets and water pump and spindle mount.

Sounds like a lot of money, but those three things were the most expensive components and about 1/3rd of the total build cost.

I won't go into further detail about the import duty, but trust me don't be concerned. You'll get a text or email when the parcel arrives in the UK and you just pay online.

Thanks Andy - thats good to know. I'm spending a bit of time trying to learn fusion 360 and draw the thing now before I buy anything else !
I added an extra extrusion 120x40 to my order, so now have a 90x90 and 120x40 piece @1200mm to factor into the (sort of) L shape gantry design.

Ryan

[CNCRY]

OK so I've figured out enough of Fusion 360 to model something - not going to win any awards but at least it's clearer and I can edit the design as needed.







The blocks on top of the X carriages are set to 40mm thick currently
All rails are 1000mm , to be adjusted if needed
Aluminium profile on gantry is 120 x 40 with 90x90 on top.
The purpose of the ballscrew and ballnut running inside gantry plate is to allow an L angle (or perhaps long brush) to be fixed to the extrusion above the screw and cover the ballscrew from dust/chips
*

Issues I'm thinking of so far is the the Z axis clearance isn't huge, 125mm from top of baseboard to bottom of gantry, although probably OK for my needs.
The Z design with rail on front and top is based on the fact Z clearance would be even lower if I put rails on top/bottom of profile. I plan to add extra C shaped plates to side of Z axis to strengthen - will it be enough/OK design?
Y axis travel is limited by how far forward Z is - losing about 275mm so probably need to bring the carriages closer together and gantry plates narrower, maybe mount motor to back of gantry extrusion instead with pulley.
Any comments on those bits? thanks

Aluminium profile arriving tomorrow - only thing I've ordered so far, but will be good to get a feel for size. Also built a 1.2m square workbench for it , 25mm ply top and 50x100 wooden frame on castors, hopefully that'll be rigid enough.

Ryan