A Process Improvement Story

A Process Improvement Story.

Back when I worked at Westvaco we had a need to change large heavy rollers called impression rollers. These impression rollers were changed about once a day and there were eight of them in a machine.

The process used for over 20 years was the one recommended by the printing press manufacturer. The process involved using a hand crank lifting table to raise and lower the rolls into place. Since the table lifted form directly under the roller, the paper web had to be cut in order to remove the roller. The web had to be taped back together afterwards. These tape splices were always difficult to get through the remainder of the printing press on start up.

We knew that on another brand of machine, they used a tray to catch the roller and the press had more travel in the impression roller mechanism so that the roller could be raised and lowered out of and into the tray. The tray was cantilevered so that it could slide between the roller and the web.

We decided to try to mimic the design of the other machine and provide a way to avoid cutting the paper. However, our machine was not capable of raising and lowering the rollers so we still had to have the capability of lifting the rollers.

We designed a hydraulic lifting table that was cantilevered from the operator end. The lifting bars rolled up and down on a post using roller bearings. The hydraulic cylinder was foot operated so that the operator could use his hands to align the roller into the bearing caps while he lifted it with his foot.

The lifting bars were narrow enough to slip between the web and the roller. We used webbing between the bars to support the roller so that it could be handled without damage.

The first prototype was very large and cumbersome as we were unsure of the strength needed to handle the rollers. Future versions were scaled down to make them more maneuverable and easier to handle.

These machines cost less than $2000 each to build. They were very simple to operate and completely reliable.

Down time on the machine cost about $1000 per hour so these machines paid for themselves almost every day they were used due to the time saved form not having to cut and splice the web.

I still have one of these machines in my shop and I use it for all sorts of lifting applications. It makes a great transmission jack. It is especially good for handling a heavy Jeep Transfer case transmission combination.