Hi
Can you suggest some servo press brands?

Application:
press an 8mm three legged flag type Terminal into the printed circuit board (PCB).

Requirements
1.-Range Force 0-3 kN.
2.-Stroke 300 mm
3.-Speed 200 mm/sec
4.-Voltage supply: 480 VAC
5.-Force Distance Control (Load Cell & LVDT)
5.1 Precise positioning control +- 0.01mm.
5.2 AccurateForce Transducer system (+- 0.5% of nominal force range).
6.-Integrated Anti-rotation.
7.-Integrated Holding/Safety Brake.
5.-Servo Amplifier Data bus: Rs-232|Ethernet

The only options I know are TOX PRESSOTECHNIK and PROMESS (both are excellent products) but is out of my budget

Thanks in advance

 

Hello,

I thought these guys are priced decently as compared to servo press vendors. I'm not sure about all of your specs but you can buy the actuator from these guys and use a motion controller/amplifier from another company such as Galil, delta Tau, Elmo, etc. You will have to build your own in some sense, but if you are looking at a specific application that you don't have to edit the force/displacement curve much than you are not needing a general purpose servo press capable of easy setup.

http://www.exlar.com

Depending on your force resolution and the friction and gearing ratios you can use the current (torque) actual reading as a representation of force. If you are doing this type of thing I'd probably use Delta Tau since they have the versatility and performance for this type of thing.

I'd ask Exlar if this is possible with their actuators and what you can expect for resolution in the system.

Good luck,
KEJR

 

I don't want to name any names here, but there is a brand of servo press that you have heard of which I would definitely avoid. My experience with them was they had a famous brand name and charged a lot of money, but had a very poor product and no support.

It turned out that their product development effort consisted of buying the mechanical components from one company, getting another company to supply a modified version of an off the shelf servo, and then outsourcing all the software to a contractor. This all sounds like an MBA's business dream for how to run a company, but the end result was that nobody at their company had any clue how the thing really worked or whether it even worked at all. We had to explain some very basic concepts to them about how parts of their system worked.

To get to some specific problems:
- Some essential features in their servo controller simply didn't work.

- The supervisory software (which ran on a PC) was very buggy, and again many essential features simply didn't work at all.

- Documentation was almost non-existent.

- Accuracy of measurement was very poor.

- Phone calls and e-mails to the manufacturer would go unanswered for weeks. When a reply was received, it never resolved a problem.

None of these problems were apparently ever going to be fixed because nobody was working on them. They had no idea (or so they claimed) that important features didn't work until we complained about them. After applying a great deal of pressure for them to do something, they would send a rep to our place, fiddle with the software for a couple of hours, and then leave after having fixed nothing.

The load cells the servo press came with were the type which bolt onto the side of the frame, and they used the encoder for press position feedback. Neither of these is very accurate. We had to use an in-line load cell and an LVDT built into the tooling, which I suspect you will need as well. They liked to talk about how you could use servo current for force feedback instead of using a load cell, but the accuracy of that is so poor that if you can use that at all you probably don't need a servo press anyway. Their transducer feedback signals were bundled through the servo cable, so we had to run our own cables to avoid the resulting noise.

We would have been better off just buying the screw ourselves (from the same place they did) and adding an off the shelf programmable servo drive. If you decide to go this route, then you will want a sophisticated drive with advanced programming features, not a cheap one. The drive will need analogue inputs for the load cell and LVDT so the press program can use them. You want a drive that can control everything by itself. Don't take a cheap drive and try to stick extra functionality onto it (I could relate some horror stories from reputable suppliers about that as well).

If you use this approach you will have to find a device or write some software that will give you force versus distance graphs. You absolutely will need something located on the machine that will continuously and accurately measure and display force versus distance graphs for each cycle. If you don't have this, then don't bother trying to do a force versus distance profile manufacturing process and just stick with a pneumatic or hydraulic press.

For the off the shelf servo press that I mentioned above, the data collection had some spectacular bugs, so that wasn't a factor in their favour.

There is another brand of servo press with which you will be familiar (which I also won't name) whom I would have more confidence in. I wasn't the person who evaluated either product (just the person who was stuck with trying to make it work). However, unlike the first company they seemed to know what they were doing when I spoke to them some time later about a similar application.

If you want to buy an off the shelf servo press, then the best advice that I could give you is for you to research in detail how your process will work and draw some graphs of what you expect to see. Then make some prototype tooling and get the supplier to do a demo for you using your product. Make sure you really understand exactly what is going on in every stage of the demo.

To go over your specs in detail:

> 1.-Range Force 0-3 kN.

Don't oversize the press too much, as that will cut into the degree of control you have.

> 2.-Stroke 300 mm

Don't oversize this too much either, as you will narrow your available options too much.

> 3.-Speed 200 mm/sec

You will have traversing speed, approach speed, and pressing speed. Your traversing speed is just to get in and clear, so this matters only for cycle time. Approach speed is where you are looking to come in contact with the part. Pressing speed will be while you are in contact with the part. This can be a lot slower than you might expect.

>4.-Voltage supply: 480 VAC

Don't get too hung up on this, as you can always put a transformer in.

> 5.-Force Distance Control (Load Cell & LVDT)
> 5.1 Precise positioning control +- 0.01mm.
> 5.2 AccurateForce Transducer system (+- 0.5%
> of nominal force range).

The load cell should be in-line between the press and the work piece. The LVDT should reference off the work piece itself (not off the frame of the machine). You would use the servo encoder for positioning control, but the LVDT for confirming measurements for pass/fail.

> 6.-Integrated Anti-rotation.

This might have to be part of your tooling design.

> 7.-Integrated Holding/Safety Brake.

You will definitely need this. If you build your own press from components, then you can always add a standard brake also.

> 5.-Servo Amplifier Data bus: Rs-232|Ethernet

I don't know what your machine looks like, but if you have a complex machine, then you will need a cell control PLC as well.

For the off the shelf servo presses, you typically need:
- The press controller runs the press cycle autonomously. It just gets a start signal and then replies with a "done" and "pass/fail".

- A PLC controls the overall cell (conveyors, lift units, etc.).

- A PC runs the press programming software and the system monitoring software. It uploads the force/distance data from the press to display it on a graph on the screen. The PC isn't doing any real time control. The press controller does that. The PC is just getting the data after the fact and displaying it. You can probably use a flat panel PC for this.

 

P.S. - I forgot to add one important point.

>5.1 Precise positioning control +- 0.01mm.

The way you will need to do this is:

1) Press to a position close to the required point,

2) Measure the actual position (referenced off the work piece, not the machine frame).

3) Calculate how much further you have to go.

4) Move the final distance.

You may need a "fudge factor" if there is significant spring-back in the part. Alternatively, you might need to back off, measure, and press again.

 

I would request you to go for Baldor serv motor there ou can get good support.

 

Hi

Use Allen-Bradley MPAR or MPAI with KINETIX drives, single or multi axis

 

What are "MPAR" and "MPAI"? I thought I knew the A-B motion product line pretty well, put I've never heard of those.

-James Ingraham
Sage Automation, Inc.