[Muzzer]

You should make sure that you are sitting down when you receive the quote for a harmonic drive of the correct size. However, you can buy pre-owned examples from ebay dealers in South Korea and China. The prices are still significant but still quite a bit less than a new one.

Looks as if a 45 or 50 size drive would be required. https://www.harmonicdrive.net/produc...-units/shg-2uh

Most of these cnc benders use internal mandrels to stop the tube collapsing. Basing it on a basic Baileigh(?) machine doesn't sound like the greatest idea.

[garthos]

You should make sure that you are sitting down when you receive the quote for a harmonic drive of the correct size. However, you can buy pre-owned examples from ebay dealers in South Korea and China. The prices are still significant but still quite a bit less than a new one.

Looks as if a 45 or 50 size drive would be required. https://www.harmonicdrive.net/produc...-units/shg-2uh

Most of these cnc benders use internal mandrels to stop the tube collapsing. Basing it on a basic Baileigh(?) machine doesn't sound like the greatest idea.

at the begining I wanted to reuse the dies from my manual bender but no way it's not gonna be possible, so it's ok I will draw it and there is a workshop near my house that can machine it.

What I'm designing now is a CNC mandrel bender,

I already solved the problem of feeding part (Z-axis) that is going to be ensured by a rack and pinion and 2 guide way from Hiwin, and the rotation of the tube, it's basically a rotary chuck that have 2 servos, one to control the opening and closing of the chuck and one to control the rotation of the tube.

now I'm starting the bending part, the bending will be a bending arm bolted on the geared servo motor, and the clamping system will be on this arm made of a linear actuator using a servo that will push the clamping die.
Then will come the controlling part and it's gonna use some Arduino based PLC.

So for now I think the most suitable i found is this geared servo from Nabtesco but as i was saying earlier I gonna have to wait 1 or 2 months once it will be ordered and i still didn't receive the price:
https://precision.nabtesco.com/en/products/detail/AF-N
So I'm looking for alternative

I also saw this:
http://www.apexdyna.co.th/index.php?...e&Id=539968170
but I'm not sure if it suitable, I'm trying to look at what is available here in Thailand, so there is principally Japanese, Taiwanese brand but I really have no clue about gears...

[garthos]

You should make sure that you are sitting down when you receive the quote for a harmonic drive of the correct size. However, you can buy pre-owned examples from ebay dealers in South Korea and China. The prices are still significant but still quite a bit less than a new one.

How much should I expect for such gear?
I'm expecting to pay around 1500$ for the bending servo and gear as it's the biggest one and it's about few hundreds dollars for the other axis servos, it's just a guess to be honest.

I'm close? or very far?

[Tinine]

Did this CNC Bender ever happen?

[servtech]

Did this CNC Bender ever happen?

Doubt it
You need hydraulics to generate the bending moment needed for pipe, using proportional control valves and encoders for feedback.
Not servo motors.

[Al_The_Man]

Doubt it
You need hydraulics to generate the bending moment needed for pipe, using proportional control valves and encoders for feedback.
Not servo motors.

My experience also, per post #10.

[Tinine]

United States Patent 5,862,697
Electric CNC Tube Bender. That's my name on it.

All the big-name CNC bender manufacturers now make 100% electric CNC benders. I started the whole thing but was never really a fan. Much prefer the hybrid approach.

There has been mention of proportional valves; not strictly necessary. Take a bang-bang (directional valve) with DC coils and PWM the coils. Horrendous deadband/hysteresis but if one has control of the PID, this is easily compensated for. When forming a tube, the bend-arm only needs to hit a target.

Distance Between Bends (DBB) is the Y axis
Plane Of Bend (POB) is the B axis
Degree OF Bend (DOB) is the C axis

And this is how a CNC tube bender is programmed - Lengths, Rotations, Angles. No G-Code involved.

It's a real shame that nothing came of this project

Regards,

Craig