Injection Molder

[Eaa628]

I'm looking at using an Automation Direct PLC for an injection molder. Is there anyone out there that may have a baseline ladder that I can look at or point me in the direction of one either AB, Cutler Hammer or Automation Direct?

Any help would be great

Thank You
Erik

 

[ChuckM]

http://forum.mrplc.com/index.php?act=Downloads&CODE=02&id=20

This is an Allen Bradley example. I haven't looked at it to be honest, but surely this can help.

Allen Bradley also has or had the Proset code for their SLC 5/04P processors for download on their site.

 

[bwheat]

Unless you have really, really, really simple injection molding machine the code on the MrPLC site will not help much. The Proset code might help a little but Proset wanders off in to the "Proset" area of the processor and comes up with answers that are not solved in the ladder diagram. The Proset code will give you a general idea of what it will take to run an injection molding machine. If you dont have LOTS of time to figure this out you might want to consider contracting this out to somebody who has done this before. Personally, I have never worked on an injection molding machine with AD on it but I bet it has been done.

Good Luck!

 

[Jiri Toman]

Go to AB

Allen Bradley has the most complete solution for Injection molding.
There are many issues involved in designing controls for injection
molding process. It's not simple. AB has two intelligent modules
that work in conjunction with the CPU (SLC500 or PLC5). One for Inject end and one for clamp end. The Injection molding module
1771-QDC is the most complex module I have ever seen.
To take some of the complexity out of the design and to shorten your design time I suggest that you use the Proset software.
If you have never been exposed to the injection molding process
you have your work cut out for you. You also need to understand the
hydraulics involved.
If you choose not to use the Proset software you will need to develop
somewhere between 50 to 150 screens for the process. I did one machine with about 100 screens. I would like to mention one more thing, if you choose not to use AB make sure that the PLC vendor has
separate modules for the inject and clamp ends. There is no way that you can accurately control either the clamp or the injection unit with the ladder!!! They might be telling you that it is possible but take it from me you will not be able to produce high quality small parts without dedicated modules doing very precise switching of
hydraulic valves.

 

[ChuckM]

Unless you have really, really, really simple injection molding machine the code on the MrPLC site will not help much.

Good point. If one is only going to operate the basic machine functions, clamp opening and closing, injection, screw rotate, part eject, etc. The AD controller will be more than enough. temperature control, injection velocity, pressure etc. is another matter. However even those can be done without the Proset logic or 5/04P.

 

[Jiri Toman]

clamp end control

Injection molding machines (Arburg, Engel, Sodick etc.) have usually accuracy of at least 0.001 Inch on the clamp side. It's because when you do the clamp close slow down just before the halves touch, you will only be a very short doistance from the kiss point and so you need to be accurate.
If you are running at 10 Inches/sec (which is normal) you need a scan time of 100 microseconds or less to be able to deal with 0.001 Inch.
Allen Bradley has originally come out with only 1771-QDB which was
not able to control the clamp side. I was one of the early users,
on the bleeding edge of technology.
I ended up arguing with late Frank Dyke of AB on that issue.
I have eventually come up with a custom PC board to bypass the PLC when controlling the clamp close. Subsequently AB has released
a module for the clamp side.
If you are looking to control a large molding machine that produces
parts that don't need tight tolerances (buckets) you may be able to get away with just the ladder on the clamp side, but if you have a machine that produces intricate small parts you will need a clamp
side module.
If the mold slow down point is not accurate enough, you will either
not close all the way or you will slam the mold. Molds aren't cheap.

 

[bwheat]

I have worked in a plant that used AB 5/03's that were not 'P' on injection molding machines. Every thing was controlled from ladder. We had 5/05P machines also. I did not see any difference in performance. These machines were not making "buckets" but the clamp was not moving real fast either. I think the machines that were not Proset were easier to troubleshoot.

 

[jonton]

I would like to see some good ladder for an injection machine too.
I know the ladder on a Battenfeld is about half a phone book.
I saw an 1800 Johns machine with an AD controller about 10 years ago. Sort of worked ok, buckets etc, but screen update was about 20 secs.
Some people have systems already made for you to instal. Techmation or Barber-Coleman come to mind. Whilst Techmation is more basic, for most small machines, its so cheap, you wouldn't make your own. I just did a quick google, saw the equipment, but not their actual site.

 

[Peter Nachtwey]

That is why there are hydraulic motion controllers

A good hydraulic motion controllers can take care of the injection cycle and clamps. It can even control the pressures in in the pack, hold and platicizing phases. The PLC can then do the slower tasks such as heater control and HMI update. A good hydraulic motion controller will have an Ethernet interface that will allow easy uploading of the injection profile and communications with the AD PLC.

 

[Eric Nelson]

That Nissei PET blow molding machine I stuck a DL405 a while back in has been cranking along 24/7 for the past few months. Not a big deal for the 405, because there are no analog controls (beyond barrel temp control). Speeds and pressures are all manually set, so the PLC is just controlling the sequence. Only 2475 instructions, and most of them are for alarm handling...

Next up for me is a very similar machine, but this one will have analog controls for the injection unit. Pressure and position feedback from the screw, and a proportional valve to control injection speed. Currently, they have a standalone controller for the injection unit, but I'll be integrating this into the PLC. Should be interesting... utoh

You wouldn't want my code because it's simply a translation from the original Fuji PLC code which took me a while to figure out. Without seeing the actual machine running, you would be lost. Also, the fact that this is a PET machine makes it quite useless to you...

I plan to write the code for this next machine from scratch, using the knowledge I acquired from doing the first machine. Perhaps THAT code will be helpful to you, but by then it will be too late...

beerchug

-Eric

 

[ChuckM]

That Nissei PET blow molding machine I stuck a DL405 a while back in has been cranking along 24/7 for the past few months. Not a big deal for the 405, because there are no analog controls (beyond barrel temp control). Speeds and pressures are all manually set, so the PLC is just controlling the sequence.

Exactly. A lot of New Britain, HPM, Van Dorn, etc. molding machines made a lot of money before PLCs were even thought of. Being as the original question was posted here, I doubt the project in question is looking to replace a full blown process controller. And if that is the case, getting the original electrical schematics and developing a ladder frome them will help a great deal. Quite often there is still a lot to be said for following the KISS principal.

 

[dandrade]

For Jiri Toman

I am of the part that does not know details.

The Proset code will give you a general idea of what it will take to run an injection molding machine.

What make this software?Funtions control? and link.

PLC vendor has separate modules for the inject and clamp ends

As thus, you are machines need special modules? So that functions are mentioned

 

[ChuckM]

Re: For Jiri Toman

What make this software?Funtions control? and link.

Allen Bradley. www.ab.com As I mentioned earlier, I believe the Proset code (SLC logic and Panelview apps) are still a free download from them. With the Proset code, you need a special 5/04 processor called the 5/04P. The 5/04P has some kind of magic in it that makes it all work from what I understand. You will also need at least one FIO4V fast analog input output module and a BTM module.

 

[Peter Nachtwey]

Explain this

If you are running at 10 Inches/sec (which is normal) you need a scan time of 100 microseconds or less to be able to deal with 0.001 Inch.

The feed back from the MDT does not update every 100 microseconds. What good does it do to scan faster than the update time of the MDT?

 

[electrified3]

What type of injection moulding are you doing? Liquid, pellets, metering? I recently programmed a polyurethane metering system, that did injection moulding on 4 parallel hydraulic clamping press's. It was all done using AB 5/05 processors. What type of logic are you looking for??