One of the questions for you would be, do you want to go with an all electric or with a hybrid? For sure you want electric controlled injection at least for the shot repeatability. There are a lot of good brand injection molding machines out there mechanically. I lean towards the machine being user friendly. It has to be well received by the floor not by the engineering staff. Of course it also matters what part of the world you are buying for as the service can be an issue in different areas.
I’m assuming your needs are for the USA. I prefer the all electric Roboshot, but would also recommend the Sumitomo and the Nissei. Probably in that order. I think you should get with your local reps and make short trips to see the injection molding machines running and take someone from maintenance and the floor with you. Most of these folks will also give you an injection molding machine to trial, so depending on the time you have that is also, a good way to go.
Normally you will have to pay for the set up and the rigging at least one way. For the Roboshot you can only go up to 330 tons, then if you want to stay with the same excellent service from Milacron you could go to the Powerline for tonnages from 330-1125. The only issue you might have there is the two different types of controllers BUT the Powerline controller is also extremely user friendly. The Sumitomo Electric goes up to 606 Tons and the largest tonnage on the Nissei is just under 600 tons unless you go with their very good hybrid which is just below 800 tons. Some folks mentioned Toshiba which I can’t comment on but they do go up to 950 tons with their electrics. Check and see if your area will give you any incentives for buying electric. Electrics are well worth the extra you pay but any state incentives could make it a no brainer.
I started out in the late 60’s and early 70’s. There have been many, many brands since those days!! The last 10-15 years have been processing mostly with Roboshot, Sandretto, Nissei, Demag, Arburg, Toshiba and Krauss-Maffei. They all have many strong points and few, if any, negatives, but if I had to choose, it would be a tough call between Roboshot and Nissei. The last year I’ve been investigating Haitians and am impressed. They have the most user friendly controls I’ve seen; their components are made in the US and Europe, as well as assembly in China and they have all the bells and whistles. I am presently working with management to possibly bring 2-4 of them in house.