Use of ultrasonic knife in plastic modelling

"Cuts plastic like butter"

The Japanese company Echo Tech started supplying ultrasonic cutter ZO series to the hobby market in 2001. In another 5 years, its second generation came, and then the third in 2012. However, they were still products intended for the Japanese market. It was only in 2016 that the production of the current ZO-91 model, which is sold worldwide, began. As a next step, the new ZO-95 model was put on sale in 2020.

Most knives are manufactured by Honda Electronics.

 While the ZO-91 model is intended for hobby use, the ZO-95 type is intended for professional use. Of course, the principle is the same for both types. The blade oscillates at a frequency of 40kHz, most of the blades in the offer are suitable for use with both types. So what is the difference between the two products? By way of execution and control. The most important differences are the following: ZO-91 has 2 levels of power available, ZO-95 has 3 levels. The ZO-91 has a power switch located on the handpiece, while the ZO-95 has a foot switch. Another difference is the cutting time setting. Since the device heats up quite intensively during operation, in addition to the thermal fuse inside the unit, the software limits the operating time according to the power used.

 Thanks to the wide range of blades offered, the knife can be used for a variety of tasks.

Cutting

- This is the basic function of a knife. In addition to standard blades, special blade designs are also available. In addition to the extra thin blade, there is also a cemented carbide blade and a zirconium ceramic blade. In addition to plastic, the knife reliably cuts resin, 3D prints, thin laminate, cardboard.

Engraving

- Another interesting option for modellers is a chisel replacement head.

Grinding and polishing

- with special flat or rounded attachments with 80 to 1200 grit designed for grinding hard surfaces.

Welding

- joining vinyl strips with a welding attachment.

It is interesting to see where the knife is already being used. Of course, the knife is widely used in model making. Not only plastic, but when building RC models, making dioramas and creating figures.

Manufacturers of prints on 3D printers are leading to a large expansion of knives sales. Removing supports is easier and significantly faster. With a knife, you can quickly remove the print from its supports, so there is not much left for the final sanding.

Grinding is used in the production of molds, even in dental laboratories for dental prosthesis production.

In Japan, where the use of ultrasonic cutter ZO series is most widespread, the knives have also found their way into museums, where they are used, among other things, to clean petrified fossils.

What are the advantages of using a knife in plastic modeling? Easier separation of parts from sprues. If the modeler is skilled enough, he can separate the part in such a way that there is no need for more sanding. For weak and thin parts such as antennas, it is possible to separate the part without subsequent grinding. It is possible to separate parts even from fragile plastic without the part falling apart, which may happen if you use pliers or a saw.

The knife is priceless if you build resin kits or use resin accessories. Long cuts with a razor saw with a large amount of sawdust are eliminated. You are able to work the casting perfectly with a knife, so there is no need for long grinding. The time saving is considerable.

Another advantage of the knife is that if you happen to glue a part incorrectly, thanks to the knife, in many cases you'll be able to correct the mistake very easily.

Video showing the knife used by Zdenek Šebesta you can find on the YouTube channel Plastic modeling.

You can find other videos of the use of EchoTech products on their YouTube pages and other social media.