3D AutoCAD MODEL

Developing a 3D model in AutoCAD was part of the design process of this project. The 3D model acts not only a great image for presentation purposes, but also as a technical drawing with the option for an exploded view. Each component in this 3D model was designed to the correct dimensions and was used as a part schematic in the fabrication process.

All parts were fabricated in the shop using the following equipment: oxygen-acetylene torch, MIG (SMAW) welder, lathe, mill, band saw, and an electromagnetic drill press. 

Only a few components were commercial products (mostly bearings). Commercial components mounted to the machine included a hot glue system which glued the film between the paper webs, and a vortex blower, which created an air hockey like effect on a roller so that the paper web could slide without friction over it. 

Three Web System

A quick video demonstration of the machine in it's final stage of development:

OVERVIEW

The three web system is an auxiliary machine component, meaning that it is an additional feature to the bag forming machine. In general, the bag machine consists of several key components: The unwind station, where paper rolls are loaded onto a roller which allows paper to be fed to the machine. A print press, where many color stations transfer ink onto print plates and then onto the paper. And finally, the bag forming unit, which forms and cuts the paper web, then folds and glue the end of each cut segment, producing a paper bag. 

The three web system goes between the unwind station and the print press. What it does is splits and separates the paper web by some set length, then applies a plastic film down the center. Hence, the name three web (paper - film - paper). You've certainly seen the product of such a device in the bread isle of the grocery store. If recall the french bread inside a long, thin paper bag with the window (film) down the center, there's a good chance it was produced by the machine I built. 

Note that this is not a machine of my design. This type of machine already existed, I was simply asked if I could reverse engineer it. I was told that the machine was on the order of $70k and the lead time would be several months on account of it being shipped on frieght from France. My job was to come up with a better deal for the company, which I did. I built the machine for less than $3k and in one months time. 

BREAKDOWN OF TIME SPENT ON PROJECT

Since this machine was reverse engineered, very few changes were made and little went into the design process.

 The original machine consisted of a knife similar to a round pizza cutter which was mounted to a heavy solid steel roller which was turned by a belt connected to another large roller which was powered only by the friction of the paper web moving over it. This was a silly design and generated too much tension in the paper web, sometimes causing tearing of the paper.

I replaced these large rollers by a small braked that mounted to it nothing more than a box cutter blade that could be engaged and disengaged. This little blade has a long life span, is easily replaceable, and generates negligible tension to the web.