Insert title near side

The title seems like it’s a bit wacky, but that’s a note you might see in a blueprint if you’re in one very important department in a sheetmetal manufacturing facility… This department can be known by many names: “Pemming”, “Insertion”, and a few others. For the sake of this post, we’ll just call it pemming.

If you have ever taken a desktop computer tower apart and noticed some threaded studs jutting out of the side of a panel inside, you may have wondered “how did that get there?”. Or maybe you never even stopped to question it.

The pemming department is crucial in a shop that specializes in fabricating sheet metal enclosures, because often times the customer will want to mount something inside of that enclosure without fishing hardware through holes and having part of the bolt exposed to the outside.

So, is this process simply for cosmetic purposes? Well, no, it’s not.

When the business or their client goes to assemble a unit, they’ll need to pay out labor for that, and when half of the hardware is already present – that cuts cost!

What is a PEM?

Well, a PEM is actually like the “bandaid” of the sheet metal world. Since it is a brand name, and not a “thing”. A brand owned by Penn Engineering, founded in 1942 and leading the fastening industry.

These were designed to install in sheet metal that was too thin to be tapped/threaded. This invention opened up doors to producing lighter products out of sheet metal.

What does a pemmer do?

To be honest, they’re master print readers (or should be very proficient in reading blueprints). This is because the department they work in has to identify:

  • Which area of the part is shown in the drawing
    • Sometimes a job must have fasteners installed before the part is formed (meaning they could be looking at a complicated box in its’ flat pattern).
  • Which side of the part should the fastener be installed from.
    • [In the views on the blueprint, a fastener is usually drawn and a note will show “install far side/near side” or “protrudes far side/near side”.
  • Which fasteners need to be used.
    • [Studs, nuts, standoffs, pins, tie downs, etc].
  • What type of material is the main part?
    • [Aluminum, titanium, steel, stainless, brass, copper, etc]
  • What material is the fastener made of?

Much of the time, the operator is not given all day to evaluate a blueprint. Their job is to be able to read the blueprint, and get the job processed and through their department quickly and efficiently.

Though mistakes happen, the operators’ supervisor will not be pleased with a worker who is slow and/or not print literate while working in pemming. (or anywhere else in the shop for that matter).

Apart from reading a blueprint, the operator needs to have the knowledge of the machinery their working with.

Some models of the machines used require mechanical user input for the pressure.

These machines require regular maintenance, safety checks, and care during use.

The operator must be able to use either written procedures or proper judgement with their knowledge of the department when operating.

The Machines

Full size, vertical fastener insertion machines have a few components in common with one another.

The machine is level, and quite heavy/solid. The heavy part is the hydraulic motor that produces the pressure.

The used portion of the machine juts out from the motor area. It’s similar to the way a drill press is set up, in that it has a lower stationery anvil and an ram that comes down from directly above to apply pressure to the work piece resting on the anvil.

These machines have pressure adjustments to pressure harder or lighter depending on the fastener being installed, and on which material it is being installed in.

Tooling for the upper ram and lower anvil must be changed out depending on the hardware as well. Since these machines press in fasteners, the main purpose is to have the tooling slide over the hardware and press (or “mushroom” out) the material while driving the fastener into the material like a friction/high pressure fit.

It’s actually an ingenious invention and the machines are a joy to run. I have particular experience running machines made by Haeger which happens to be owned by Penn Engineering (who also manufacture fasteners).

However, there are other machines for this type of work. Older generations of workers would be familiar with machines like the PEMSERTER presses.

Though the machines make life much easier, there are hand tools that can install fasteners as well; both a pneumatic model and a manual model exist and can be purchased from Penn Engineering.

Make the best product possible

Does every shop need to use these machines and this process? Absolutely not; it really depends on the market they intend to service and the products they’ll be making.

Some companies may never need to install hardware/fasteners into their products, while others make their living on jobs that require this process in every part.

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