Electrical fault: Cycle stops midway through

[Alex Bedford]

Hello guys,

Just joined (from Scotland).

I have a small 35t injection moulding machine - it's old (1998). Made by Boston Matthews. The problem I have is that it has developed an electrical fault, the cycle stops when the barrel goes forward. The nozzle makes contact and then the machine won't progress to injection. If I switch to manual operation I can go through each part of the cycle without problems - I could stand there all day making little end-caps for my 'keyloops'! But on 'auto' setting, the machine now only gets as far as barrel forward. All the micro switches I've tested and are fine (mould closed, nozzle guard down, barrel forward etc). Any suggestions would be greatly appreciated - in this area, electricians that know anything about injection moulding machines are difficult to find!

Thanks,
Alex

[iautry1973]

I am not familiar with that machine, but you said you tested the microswitches and they work, but did you test to make sure they are being tripped when the nozzle is all the way forward? I would take a look at it this way...after the barrel moves forward what is it the machine needs to see next before moving forward in its cycle? Most machines would want to see that the nozzle has reached it zero point. Plus guards are closed, heats are up, the screw is in the correct position, mold is open, ejectors are back, etc.

[Pilot]

The question is how the machine is tripped to injection. by position? by hydraulic pressure increasing? (and stupid question- do you have a injection delay set to zero?)

[Platt1990]

My question is about the barrel forward position. Is it a set point by inch.(mm,cm,etc.etc.) or hydraulic pressure. If it doesn’t see it’s zero point it will cycle through to injection and stop there. Same with hydraulic pressure if it doesn’t see the pressure it wants for barrel forward it will not proceed to injection I had early 90 model milicrons do this

[Alex Bedford]

Thanks Iautry,
Yes I've checked all of the settings - they've been a constant.
Thanks,
Alex

[Alex Bedford]

Thanks Pilot,
It's tripped to injection by i) mould closing ii) barrel forward.
I've been trying to understand the wiring and all the components, the wiring diagram doesn't detail the name or function of the many components and so it's been difficult for me and I've been stressed! I changed a couple of relays that had wire numbers relating to the injection solenoid or the barrel forward - but exactly the same, it stalls when it gets to the point of injection. Then on manual operation it works perfectly. I kept looking at a large red 6"x 6" component the many wires going in and out of the terminals: Telemecanique GEK. I looked it up on the web - and it's a sequencial machine relay. This must be the issue, it's not moving on to the next function. So I've ordered one on ebay as they are no longer manufactured (machines use PLC's these days.
Thanks for your help,

Bye, Alex

[Alex Bedford]

Hi Platt,
barrel forward is recognised by tripping a limit switch. The machine injects OK on manual. Here's my solution (I think):
I've been trying to understand the wiring and all the components, the wiring diagram doesn't detail the name or function of the many components and so it's been difficult for me and I've been stressed! I changed a couple of relays that had wire numbers relating to the injection solenoid or the barrel forward - but exactly the same, it stalls when it gets to the point of injection. Then on manual operation it works perfectly. I kept looking at a large red 6"x 6" component the many wires going in and out of the terminals: Telemecanique GEK. I looked it up on the web - and it's a sequencial machine relay. This must be the issue, it's not moving on to the next function. So I've ordered one on ebay as they are no longer manufactured (machines use PLC's these days.
Thanks for your help,

Bye, Alex

[iautry1973]

Alex,

Hoping that is the problem and you can get back to molding!

ian

[Alex Bedford]

Thanks Ian,

-I've been stressed! I even applied for a bank loan in case I couldn't get this old girl working again and had to buy another machine.

https://www.youtube.com/watch?v=O2WdZc7pj1w

Bye,

Alex

[iautry1973]

She does look old, but looks in pretty good shape from the outside

[Pilot]

Hi Alex,
could you post here a photo of panel (with sliders) and hydraulics scheme? It looks, that the tripping to injection is done by hydraulic pressure…..