Injection Molding Control

Archie

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May 2002
Location
Orangeburg, SC
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I've been asked to quote a job to upgrade controls on an old injection molding machine. The current controls are made up of about 10 separate modules networked together, each with a specific task.

I am not familiar with current methods of controlling an injection molding machine. What is the currently preferred method for controls on an injection molding machine, a PLC to control everything? The customer specifies AB. Is a Contrologix platform capable of handling all of the tasks on this machine (e.g. temperature control, ram positioning, etc.)?
 
I worked at a plastic factory for about 4 year. we had to high pressure injections machine. there were controled by old 286 computers. allways wanted to upgrade them to a new control system but they would never speand the money. controllogix would do the job. i know they make a card for controling barrel temps for the slc500 so i am sure they make one for the controllogix
good luck
 
Key questions.

How critical is the pressure control? How critical is the repeatibility? Finally, what are you making. If you are making plastic cups then this isn't critical. If you are making plastic instruments of the medical industry then that is a different story. The other issue is how much time do you want to spend re inventing the wheel. Finally, the HMI screens always seem to take the most time to write and get right.

I know of some integrators that can help. A Control Logix can do the whole job depending on how you answer the questions above. However, a little DL250 can do if it is attached to a motion controller that can do injection molding by controlling the position and pressure profiles.

The key thing people seem to want is the ability to grab the data for the part just made to a crtical item is getting target and actual positions and pressures displayed quickly.
 
Archie and Peter,

You don't really have to re-invent the wheel. AB had/has two options: Proset 600 (PLC-5 platform) and Proset 200 (SLC-500 platform). For tighter control the Proset 600 uses a co-processor, the QDC module. The Proset 200 has a specialty module, the SLC 5/04P. We have both on 1500 ton and 300 ton presses.
Both come with canned software for the logic and HMI. You just add 'modules' based on the machine; Inject control, Inject and Clamp control, ect.
You can check with JVH Engineering, an AB integrator in Michigan for more info. I think they also worked with AB to develop the ControlLogix control.

Hope this helps.

Mike
 
For the slc take a look at the 1746-BTM module it a barrel temp module for extruders and injection molders, often used with the pro set stuff
 
The machine makes electrical connectors such as ones to put a plug on the end of a power cord. I have not been given specifications on repeatibility or pressure control, but by guessing the machine is from about the late 70's I would guess that it not an extremely precise piece of equipment. My hopes are not to reinvent the wheel, but to find as close to a canned package that I can.

Cost is an issue, so getting the lowest cost AB solution is what I need.
 
Use one of ABs canned injection molding machine solutions. Especially since it sounds like you are unfamiliar with PLC capabilities.


As far as pressure and temperature accuracy is concerned, don't fret it. I use AB PLCs (PLC5s, SLCs and CLX depending on age of machine) on hot presses that operate at 11,000 psi and nail the pressure setpoint +/- 1psi apparent pressure, which is much tighter than the pressure transducers. Temperature control accuracy is within 2-3 deg C. The PLC will outperform the hydraulic hardware and sensor.
 
BTalbot said:
My advice would be to wait until Eric N. posts a reply and then follow his suggestions.
My advice would be to wait until LStewart post a reply. Although I'm quite familiar with IMMs, I've only upgraded PET machines. He's done 'normal' presses (see THIS thread).

Since you are using AB controls, you must have an unlimited budget. I'd recommend their canned solutions as well... :nodi:

🍻

-Eric

P.S. to Bob (BTalbot)... I'm doing 2 more machines, so expect an HMI order soon... ;)
 
If you are going to do AB all by yourself then get the SLC 500 ProSet 200 solution. It will cost less and the 1746 hardware will probably be around longer than the 1771 hardware. Get ready for a learning curve if you dont have lots of experience with injection molding and motion controls. There are several integrators that do this all the time. I have worked with JVH and they can do just about whatever you want but engineering time always adds up. I worked with another company out of Ohio that did a Proset 200 on a Cincinatti machine, they did a good job but I cant remember the name... HPM.. no.. Milicron.. no.. well maybe it will come to me.
 
Wouldn't say its an unlimited budget, but more of a limited customer. I made an attempt to suggest a much lower cost alternative, but with no success. We all know the infamous oxymoron:

"Use AB and keep the cost down"
 
bwheat

You mentioned the name HPM. Did you possibly mean HMP? The reason I ask is because on one of the documents on the machine has the machine type of HMP #10. If this is an outfit that does injection molding machines, maybe they have an upgrade package already designed for this particular machine.
 
Archie said:
You mentioned the name HPM. Did you possibly mean HMP?

Sorry, but he DID mean HPM (see THIS link)... :(

Years back we used to use a company called Kazway out of Ohio. The would refurbish our old VanDorns mechanically and electrically. Electrically, they pulled all new wire, and swapped in newer Pathfinder controls (which still sucked). Since I can find no mention of them on the web, I assume they're no longer in business... :confused:

🍻

-Eric
 
Now that you brought up HPM

HPM uses a Siemens package with our controller doing the position/pressure control. Our controllers has the ability to close the loop faster than a PLC and we have worked long and hard at make the transistion from position to pressure control very smooth. For the most part the PLC just needs to give the controller an execute command the the controller does all the machine sequencing. This off loads the PLC so it can to the temperature controls, HMI and safety interlocks.

Our controller can communcate with the PLC and HMI using Ethernet or Profibus DP. The advantage here is that one can load the position and pressures the last shot very quickly and display the data. This makes set up much faster. Our data in not affected by the varying scan times of the PLC or the time it takes to transfer data over the back plane. We synchronously acquire the shot data and buffer it on our controller so the HMI or PLC can upload this data at its rate. This means you get more accurate position, speeds and pressures for you graphs.

Some applications don't require all of this. The more demanding ones do.

BTW, we work with AB, AD, Omron, Modicon too. Hopefully Phil will allow equal time. There are alternatives.
 

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