electric molding machines

[Flash]

My company has always had hydraulic machines with toggle or ram. We are looking into purchasing an electric,probably used. Can you guys give us some pros and cons of electric and what manufacturer is better. Thank you

[brentb]

Use less electricity
More precise
Don't need cooling water for hydraulic oil
Quick


More initial cost

KOM

brent

[rickbatey]

Do you use hydraulic cores or valve gates? That's an issue to solve if you do. Never worked on one and I've only heard a couple issues from them. Early ones used timing belts and belt and wear created lots of dust, issues with ball screws failing (not heard this one in years), ejection had to be at zero so rod length was critical (short caused servo to keep pulling back leading to over heating) but again I think that's fixed, and long hold times or high hold psi caused servo motor over heating and I think that too is fixed now days.
We keep looking at them but since we run mostly large machines there's not much room to offset the costs.
Rick.

[brentb]

Belts... fixed
Ball screws... resolved
Ejector rods... not tied in, if tied position is critical, monitor torque on return so if you don't reach setpoint, you protect servo
Hold times... resolved on most presses
Core pull/valve gates... use auxiliary hyd unit or get electric gates/cores in mold

KOM

brent

[Flash]

yes we do use hyd. and air cores. That a good point. Thanks

[Ten Fingers]

Worked at a not very impressive molder for a short while that tried a switch to electrics. Ran into a ton of problems with ejecting parts. Most of their parts hung up on the ejector pins and an electric can't slam the ejector plate into the stops to dislodge the part like a hydraulic can. ;)

[xsamurai]

Hi

Elictric machines are electricity saver than the hydraulic machines

It also need your maintenance and please never forget to check the grease

Grease is the life saver for your electric machine

xsamurai :)

[Brisli]

I have been running all electrics since the early 90s, they have come a long way. most of the issues have been solved, injection unit force against the mold can still be a problem when running high pressures. Tie bar spacing, die height and tieing in ejectors can be challenging. I have ran fanuc, Toshiba, nissie and arburg hybrid, sumitomo, negri bossi, hands down in my opinion is the sumitomo all electric. super fast, highly accurate. as a processor I also like the added features sunitomo gives, starting injection just prior to the clamp locking up (helps venting), and having the ability to pause under pressure just prior to transfer to allow the fill inbalances to correct before packing the parts.
The sumitomo control is somewhat complex but a far cry from the selogica. I wish the machine manufacturers would decide on one terminology and go with it.

Brian

[brentb]

Worked at a not very impressive molder for a short while that tried a switch to electrics. Ran into a ton of problems with ejecting parts. Most of their parts hung up on the ejector pins and an electric can't slam the ejector plate into the stops to dislodge the part like a hydraulic can. ;)

Yea, lack of slamming can be a minus in electrics. I hear that there is a press maker (won't say who or where) that has "SLAM BAM) option!

KOM
brent

[JayDub]

If you need “slam-bam” you probably don’t want an electric. Just like if your hockey team needed an enforcer you wouldn’t recruit a figure skater however good she is on the ice.

I’ve used small Nissei verticals and horizontals to make tiny, tight tolerance medical parts and the shot to shot (and lot to lot) consistency is superb. As noted, they’re expensive machines. At my current job we have a couple of Sodicks, which seem like good machines, but I haven’t had a chance to put them through their paces yet.

[rojo017]

I'm new in the group so hi. It all depends in the field you are. If you mold a lot for medical devices where you need precision, repebility and a clean environment then electrics should be the first option but they are more expensive. In the other hand if you do thin wall where injection speed is crucial then electrics cannot math the speed you get from a hydraulic IMM. Also I heard there hybrid system but I don't know to what extend is electric and hydraulic. Good luck

[Brisli]

we bought 4 new electrics a little over a year ago, then the euro was so high we were able to get the Japanese machines cheaper than the german hydraulics and way cheaper than the german electrics. unless you have a special need for hydraulics, I would always go electric, eventually you end up paying for it anyway without ever getting the benefits (imho)

Brian

[Pavlo]

Seems taht all important points have already been mentioned. I work with suppliers which are under changing its machine park into electrics and some of them are already after transition. What they say is, they would never came back to hydraulic. The main reasons are:
- precision and repeatability - if you mould precise parts with narrow tolerances, it is probably best choice
- less noise
- much lower maintenance costs.
I do mainly tests trials and, personally, I prefer to work on hydraulic press - hydraulic are like "less perfect", and allow to better "feel" the process - if there are any problems, it is easier for me to understand the causes, when working on hydraulic machine. When we come to serial production - electrical are great.

[brentb]

Many electrics have a feature that allows injection to mimic a hydraulic press response. Great for qualifying a mold destined for a hydraulic press.

KOM

brent