How Timing Screws Transform Packaging OperationsHow Timing Screws Transform Packaging Operations

We are all familiar with screws for fastening and adjusting. Timing screws are a special kind of screw that have many uses in packaging. They are commonly used to time or synchronize products or packages into packaging machines in the correct position and orientation for whatever operation is to be performed on them.

Instead of narrow uniformly pitched threads, timing screw threads are cut to fit the shape of the product. Another difference is that the space between threads or “pitch” is commonly not uniform from screw infeed to discharge.

Timing Screw schematic. Changeover.com

One common application is timing bottles into a starwheel on a filler. The bottles typically are bunched up entering the machine. When they reach the screw, the leading thread picks off the first bottle. As the screw rotates and the pitch increases, the bottles are separated to the desired spacing as seen in the simple screw below.

If the bottles are to be timed into an infeed starwheel, the screw and starwheel are linked mechanically or electronically. The final thread releases the bottle directly into the starwheel pocket as seen below:

Detail into starwheel timing screw. Septimatech Group

In addition to spacing and synchronizing, timing screws have many applications (see image at top). They can turn, combine, position, flip or pause bottles, jars, cans, tubes, pens, broccoli, and pretty much anything else.

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Another application is spacing bottles under the nozzles of an inline filler. The bulk of the screw is at a constant pitch to position the bottles under the nozzles. An advantage of this is that nozzles do not need to be repositioned when the bottle size changes. Simply swap the timing screw for the next bottle.

Timing screw indexing. Septimatech Group

Timing screws may be intermittent, pausing during the filling or other operation. They often operate in continuous motion, stopping only when the process is stopped. There are exceptions but generally the timing screw should turn down on the product.

A common misconception is that timing screws should push the product. This is wrong. Conveyor speeds should be adjusted so the product is being held back by the leading edge of the pocket rather than pushed by the trailing edge.

It’s easy when you know.

Find out more about timing screws and how they work. They are covered in Chapter 2 of John Henry’s Packaging Machinery Handbook. Other chapters cover inspection, flexible packaging, coding, and all commonly used packaging machinery

Purchase the Handbook on Amazon at https://amzn.to/3kr4qj7.