Lifespan of Servo motors on Haitian Machines

[tomt2]

I started looking at Haitian molding machines because of their low cost. They are built in China but they do have service and parts available in the US. They have a Mars series of machines that use a servo motor to drive the pump. The press is identical to a normal hydraulic toggle machine but with a servo motor instead of an AC motor. The servo motor only turns when oil pressure is needed. During cooling, there is no need to turn the pump after the screw is recovered. Also, pressure is regulated by the speed of the servo motor, so there is less wasted energy making more pressure than is used. They claim a 63% savings over an older Vandorn machine. With our long (60 sec) cycle times, I think a hybrid or electric machine would save us a great deal of electricity. Does anyone know about the quality and service on these machines? What about the life of the servo motor? I am thinking that it would wear out faster than a normal AC motor.

 

[Pud]

With the now universal use of variable delivery hydraulic pumps, there cannot be much difference when no pressure is called for, as a variable delivery pump will effectively be on "no load", and the motor will be idling.

It would be interesting how the oil is maintained at the correct operating temperature. The all-hydraulic machines that we have run the oil at 80 - 100 bar through an orifice to heat it up. When running or 60s or longer (up to 150s) cycles, the pump heats the oil during what would otherwise be idle time.

Yes, they are cheap here in the UK, but at what cost? Hydraulic machines also have the benefit of very mature technology, so you are not doing reliability testing for manufacturers. You will have to consider the impact of lost production when things fail.

This is not an advertisement, but we use Arburg machines as their whole UK and European operation is set up very well - the spares (used twice in four years for heater band and a thermocouple) arrive next day, the rep pops in regularly for coffee and to see how things are going. Just ordered a 150t one at 40% off current list price.

Just my opinion.

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[tomt2]

Thanks for your reply. I'm glad you brought up the oil temperature question. I will ask about that.

I have no experience with Arburgs. Some molders around here use them. Aren't they all electric now?

 

[Pud]

tomt2:

I don't think Arburg make machines as big as you require, but if you want an intuitive operating system, just have a look at them. It's not based on Windoze for a start!! I think they do make all electric - definitely hybrids with an electric screw drive - I buy the twin pump versions instead.

The OS is one of the main reasons we use them.

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

My post in the previous thread supports some of Harry's statements. It seems we both like Arburgs for the same reasons.

I have no experience with servo motors on moulding machine, but there are a number of Chinese machine of more convectional design.

If I were to choose Chinese, I would stick to tried and proven design.

As eluded to in the previous thread, at 60 second cycles,capital investment will be a more significant portion of the overal cost and power will be less significant.

Regards
Pat
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[tomt2]

I think it was the JSW that I was thinking about that have gone all electric. I also have quotes for JSW. Any thoughts on those?

I will have to find a sales guy for Arburg. I am not very familiar with the Arburg brand. I usually only see them in small tonnage machines. .....I just looked on the website. Looks like they only go up to 620T. That won't be enough for me.

The Haitian can be ordered without the Servo motor. It's essentially the same machine only with an AC motor instead of a servo motor. I agree that would be the safer route, though.

 

[tomt2]

The sales guy said the servo motor will usually last the life of the machine. Same as with the toggle mechanism. Does that sound feasible? Our old ram cincinnati machines have gone through several motors.