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Plastic speakers???

In the good old days when you sat in front of the PC to surf and looked into a 15 inch tube, it was not uncommon to have the beige speakers on your desk. This was still real hard plastic and could be produced inexpensively using the technology of the time.

In 1988 the first FDM 3D printer saw the light of day. FDM is the fused deposition modeling process, which means “melted deposition process”. In this process, a plastic thread is melted through a heated nozzle and applied in layers to a print bed. This creates a 3-dimensional body layer by layer. Over time, the term "additive manufacturing" educated. Material is added during production. When you drill a hole in a board, it is a subtractive process; you remove material from the place where you drill.

A lot has happened on the market since then. 3D printers have now become affordable. For beginners you can get devices that are priced in the €150-€200 range. Even with these devices you can achieve very good results. At around €1700 you have reached the top end of the food chain in terms of investment. From there, the devices that are used in industry begin. They don't do anything better or worse than home printers; rather, the manufacturers target special applications or enable the processing of special materials for industry.

But back to our home. The "plastic" has now become plastic. Even for us hobbyists there is an endless variety of interesting materials. PLA (Polylactide) is a particularly popular material. This is made from renewable raw materials (corn starch) and is easy to process. Some manufacturers now have over 300 colors and varieties in their range and not a year goes by when there is something new. In addition to the standard, there is now also

  • Mixtures with dusts, cotton and/or wax

  • Fiber reinforcements

  • Admixtures of mosses, seeds, leaves or wood

  • High strength or temperature resistant

  • 2 or 3 colored material

  • and combinations of the above examples

Depending on the composition, the demands on processing increase. Now to come back to the topic of speakers.....almost forgot.

A few weeks ago I drove a Royal No. 4 from BPA to the editorial team at Klang und Ton. The version with a classic wooden construction was already a guest there and a comparison could be made. Pure stress was bubbling inside me as the measurements were taken. To put it briefly, there were no abnormalities compared to the wooden version. Rather the opposite was the case. The plastic version was even able to score a bit in the lower frequencies. Compared to the wooden version, the 3D printed housing has a different shape, but with the same volume. In addition, the BR is rounded both on the inside and outside. In the listening test in your own four walls, the box also sounded a bit clogged. I then removed the studded lining and the insulation wool and replaced it with some Bitumex. Then it was nice.

This case was manufactured on a printer with a print volume of 220x220x250mm. This dimension has now established itself as a standard. Most manufacturers offer devices in this size. Even though I now have a slightly larger printer, I have remained true to these basic dimensions. You can produce all products on PRINTYOURBEAT with a printer of this size.

A speaker is usually. larger than the print volume of a 3D printer. For this reason I break down the case construction into small pieces. These are then reassembled into a body.

So that a rigid and tight housing is later created, the parts are connected using an adhesive connection (yellow). The spring shown (green) prevents the adhesive from becoming visible in unwanted places. This spring also guides the following part and creates a clean transition.

Then we still have the glue. Plastics can be real bitches if you want to glue them together. PLA can be glued very well. In my kits there are actually only 2 different adhesives that are used. We have a classic superglue. This is only used for fixing and replaces the usual screw clamps used in wood processing. The second glue is called “all-purpose glue”. Interestingly, on the back of the bottle there is a list of things that he doesn't stick, but PLA works great!

The special feature of this glue is its ability to never harden. You get a kind of hard rubber layer between the parts that creates a stable connection and seals at the same time.

In the end we get a 100% tight and rigid housing that can easily be compared to wood.



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