buying a used injection molding machine - what to look out for

[jkeyser14]

I might be purchasing a used machine locally. It's 30 years old, but they said it still runs fine and they are replacing it with a machine that has a larger shot size.

The machine is no longer under power, but what are some things I should look for? I already asked about leaking hydraulics, and they said it didn't have any major leaks.

[mc_n_g]

How worn is the screw? The barrel?
How about the bar slides?
Who was their repair man or shop for parts? Are parts still available without having to hunt to the ends of the earth for them. 70's electronic parts are not the easiest to come by. Does it have manuals and schematics (KEY here)? Without schematics you will not be able to figure a whole lot out if you have problems.
Are the tips replaceable? If so when was the last one replaced? What thread style?
Just because a company is in business do not assume they still sell parts for them. Do not go for the 'the company is still in business' and be satisfied. You need to go forth with the effort to check this stuff for yourself and see how much rates are if repairs are needed. They may remanufacture parts for you, but at a premium.
Do YOUR homework on the machine! If you can physically look at it do so.

mc_n_g

[jkeyser14]

I'm going to look at it in person on Tueday. What's the best way to tell if the screw and barrel are worn (ie, should there be a certain maximum clearance between the two?).

They are basically giving the machine away, so I'll be satisfied if it's a machine that I can learn on. If you don't count the learning experience as enough to pay the machine off, and you consider my time as being free, it will save my business partner and I money on the first run of parts. After about 4 runs, I'd be able to pay someone to pick it up and take it to the scrap yard if need be.