First Time Machine Buyer - Need Help!

[Reckless]

I have always wanted a plastic injection machine, mostly for my company's products. We make small electrical plugs (biggest device is 3"x2"x2" and smallest is 0.75"x1x1.75) in polycarbonate/abs.

Recently, I manage to acquire a 121 ton Nissei all electric machine with chiller, cooler, dryer (has only 4000 hours on it and came from a medical company). The machine is a vertical injection machine from mid 2000s. It has AC servomotor for each working axis (injection, metering, mold-open/close, ejection). I don't understand anything about plastic molding, here are the specs:

PRODUCT FEATURES
Shot Size.............................................. ..........3.3 Oz
Stations.......................................... ................Single Station
Upper Platen Size............................................25 .4" x 16.1"
Clamp Stroke............................................ .......9.85"
Min Mold Thickness......................................... .7.87"
Ejector Stroke............................................ ......1.97"
Daylight.......................................... .................17.72"
Controller........................................ .................NC9300T
Voltage........................................... .................230V

Is 3.3oz shot size kind of small for a 121 ton press? Also, was going vertical a bad idea? I do need to change molds daily depending on how fast machine will run. I would have preferred leaving the machine unattended for 30 mins at a time (not sure if thats a bad idea). If I could have afforded a new machine I would have gone horizontal hybrid. Nissei service department didn't speak highly of the machine because they said it has a toggle switch and complicated assemblies. I don't want a white elephant thats going to cost me $10-15k/year in maintenance (I was hoping to find a maintenance free machine hence why looking for low hours). Service department was claiming difficulty in sourcing many of the parts which surprised me as its barely 12 years old. I thought being Japanese it would be like an indestructible toyota land cruiser that never dies. I notice Nissei machines in many of the china plants I have visited.

Does running a plastic injection machine require lots of training or is it something easy to pick up? Every salesman makes it sound like its very easy to run but there are soo many components and buttons/variables that it looks extremely complicated- especially considering the online information on the model is near non existent.

[rickbatey]

You really should hire an experienced injection molder for a time to work on this. The injection unit must have the correct components in it to run the resin you want. Your molds must be built for this machine configuration and other things you haven’t even thought of yet.
Rick

[MTUHusky]

Rick is right, you should hire someone who knows the machine and the process to help get you started.

Your screw needs to be right for the material you are running.
Your mold needs to fit in the platen area.
Your mold opening (clamp stroke) needs to be large enough to open the mold and allow the ejectors to push the part out AND enough the physically get the part out.
You are making electrical plugs which implies to me that you are running inserts. So a vertical should be in your favor.
-Vertical can be easier to change molds (no crane needed).
If you are putting electrical inserts in the mold, the only way you are walking away for 30 minutes is with automation (welcome to another $100k expense).
Your shot volume needs to be able to fill that mold and leave a cushion (to avoid shorts and properly pack out your parts). If you put a mold in there that needs more plastic than your machine volume can put out, you need another machine.
Typical maintenance will be oil/filter changes ($100 a month), worn check rings (a few hundred bucks every few months), worn screws/barrels ($1000 to $10000 depending on size and flights, maybe once every year or two depending on resin)
Finding parts can be a pain as they are constantly changing the technology. We find a lot of our stuff on eBay believe it or not.

Sorry for the list (and that list can be a lot longer) but I am just trying to illustrate some of those things that you haven't thought about that Rick was alluding too.

Husky

[Reckless]

Great advice and I fully agree- I have been trying to find the right injection molder to guide me through the whole process in Chicago. I'm meeting with alot of molding companies, luckily for me the building I'm in was used by a large injection molder so I have a roof top water tank and alot of power wired all over the building.

I have been debating if its worth the headache to save $50-100k/year in excess plastic inventory. The deeper I get into this the more difficult it gets. The machine ran me $7k delivered. It came with a new chiller, cooler, dryer and the machine has alot of upgrades to it according to Nissei. Originally, I was looking for a low hour 2003+ 100+ ton electric horizontal machine for $5-10k but they hold their value much much higher. I like the idea of changing molds without a crane. Nissei salesman mentioned a work around.

Has anyone used PEX water lines for mold cooling? I'm trying to avoid running steel pipes half way across my building.

I am meeting with moulder #4 tomorrow to discuss designing our family molds.

[MTUHusky]

I do not have any experience with the PEX water lines. All of the lines going to our machines are metal. The line from the machine usually hooks to a manifold via large rubber lines with quick disconnects. Then we use the same rubber lines to connect the manifolds to the molds unless the material requires a hotter mold temp. which we then just connect the water to the oiler (to regulate the oiler temp) and the oiler to the mold via heavy braided lines. The PEX lines look interesting, I am going to ask my maintenance people about it.

[iautry1973]

I have never used PEX before, did see a molder use PVC for the return back to the chiller. Didn't use the right schedule piping and it deformed when we ran hot water and exploded. As the others have said, you should really get someone who is an experienced molder to come in and help get it setup and running. It can take years to get a tech up to speed so not something you really should be cracking a book open and experimenting with. Fimmtech, Paulson, Orbital Plastics, Andy Routis, and AIM all have training programs and classes you can go through. Suhas has a great book about molding. I bought about a month ago and I am about half way through it. Pretty good reference material for you.

[Reckless]

I met with a nearby molding company- great guys. They spent a few hours going over everything. In the end they recommended not to get the nissei all electric vertical machine and go with chinese brand machines and using them for a few years until it breaks completely down and then upgrade.

[rickbatey]

Im sorry but anyone that WANTS you purchase a Chinese machine is suspect !! There are low priced machines from lots of suppliers not to mention used machines. Now the one you can wanted probably wasn’t right for what you wanted to do but to purchase a press and then throw it away doesn’t sound like a sound business plan. Local custom molder here saved their money , bought a solid used press, and did so until they had all the machines they could justify. Then started again but bought new ones to replace old ones. Just my plugged nickel.
Rick.

[Trisit Biswas]

Im sorry but anyone that WANTS you purchase a Chinese machine is suspect !! There are low priced machines from lots of suppliers not to mention used machines. Now the one you can wanted probably wasn’t right for what you wanted to do but to purchase a press and then throw it away doesn’t sound like a sound business plan. Local custom molder here saved their money , bought a solid used press, and did so until they had all the machines they could justify. Then started again but bought new ones to replace old ones. Just my plugged nickel.
Rick.
Hi.
This is Trisit Biswas FROM India I need a low price injection molding machine for startup a new business if u have please let me know trisitbiswas2@gmail.com