Using a handheld packing tape dispenser gun that has been modified to fold, extrude, and cut tape into tubes, a team of researchers from the Hasso-Plattner-Insitut (HPI) at the University of Potsdam has created a method of transferring computer-generated wire-frames to the real world. Dubbed the "Protopiper" by its creators, the device is not only capable of producing full-size outline objects, it is also able to produce hinges, bearings, and axles to give them opening doors, drawers, and movement just like the real things.
Thinking outside the square, the team from HPI sought a better, cheaper, quicker way to produce real-world wireframe models than the usual plastic tubes. Standard plastic packing tape was the team's solution. Easily formed into tubes which have a good strength-to-weight ratio and already being adhesive-backed it makes surprisingly sturdy, quickly-assembled structures.
Producing extruded pipes at a rate of around 8 cm/sec (3 in/sec), the Protopiper is capable creating a 90 cm (35 in) edge tube (standard kitchen appliance height) in approximately 11-12 seconds, and a rotary encoder on the servo motor ensures that the error rate is less than 1 cm length error per meter. Powered by a 11.1v LiPo rechargeable battery, one charge is sufficient to produce up to 200 cut lengths of pipe.
Equipped with a number of electric motors, heated cutters, and all managed with an Arduino controller, one of the Protopiper's cleverest features is the employment of two stencils during the dispensing process.
The first stencil, located toward the rear of the unit, is a u-shaped one that first forms the flat tape toward its eventual tube shape as the tape moves through it. The next stencil, an e-shaped device, then forms the complete tube and wraps the tape back in on it self so that it is ready to adhere and stay in its formed shape.
Able to be extruded in pre-determined lengths to match a specific CAD drawing, the tape tubing can also be produced in any length by manually-overridng the system and holding the trigger until the desired length is reached. This, the creators say, is particularly useful for free-forming and brain-storming ideas in a space without a specific plan.
As mentioned, the tube is also cut as it leaves the device. However, the Protopiper is also able to produce different types of cuts at this point, including wing-style connectors and hinged joints. This ability allows the formed tube to be given a variety of connections or functions straight from the gun.
Bringing all of these elements together, the team has demonstrated that everything from simple, box-type furniture through to complex structures with opening doors and operating drawers can be created using the Protopiper.
In fact, according to the team, almost any functional mechanism that dangles, slides, rotates, or pops can be reproduced. This means that even a small range of simple functionalities can be combined in various ways to produce a much larger combination of movements or abilities.
To get free-formed objects back into a CAD program to turn them into design specifications, the HPI team opted to scan and digitize them using an app on a mobile phone. This process is sufficient to input a line drawing to a CAD program capable of being transformed into a blueprint for subsequent manufacture.
The Protopiper is still a prototype in the Human Computer Interaction lab at HPI. There's no word as to whether it will ever be developed for commercial use, but the team says it will be further modified to explore different diameter and curved tubes.
The video below shows the Protopiper in action.
Source: Hasso-Platner-Institut
