How 3D printing is changing the way we solve problems

Without 3D printing the mechanical design and building of the new factory in project Smarta Fabriker would not be finished on time. 3D printing helps us solve problem in a flexible and rapid way.

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Anna, Tintin and Alexander from GTG is tuning the 3D printer.

Understanding the problem and coming up with ideas

When making solutions for the smart factory, the process always starts with analyzing the problem. This involves a lot of trying, testing, observing and measuring. Working under a tight schedule can make this hard. Especially with electricians, programmers and project managers making it hard to get the space needed for a proper investigation.

That is why the virtual twin of the factory is so important. In the digital copy you can find all the parts of the factory and measure and try all you want without annoying anyone else. You can take your time and work comfortably away from the noise of screwdrivers and 3D-printers. An example of this from our factory is the making of the pedal holder. A solution to get the pedal out of the way without having to pull the cord out during transportation was needed. When solving this problem, all of the measurements were taken from the CAD model of the pedal. The holder was then tested with the virtual twin of the pedal to make sure that it fit. It was also placed in the virtual twin of the factory to make sure that it would not be in the way and easy to reach.

Pedal
The pedal, its virtual twin and the final solution for holding the pedal.

Concepts and prototypes

The second part of the process is developing the ideas into concepts and making prototypes. During this stage, different solutions are tested and the ideas are fine-tuned to perfection. This is where the 3D printers are put to work. In project Smarta Fabriker we have used them for many different types of testing, from creating small test versions of ideas to making sure to get the perfect interference fit.

Img 0808
Three different versions of the fastening bracket for the protective sleeve on the big screwdriver.

The grip for the robot on the screwdriver was also a tricky part to make. Inside it are two bearings to reduce the friction inside the grip. The parts of the grip were supposed to be easy to change, in case they broke. Therefore the hole for the bearings had to be small enough to not allow the bearings to move when the grip was used, but big enough to make it possible to take the bearings in and out of the grip. To solve the problem, different diameters were tested using small test rings, and when the perfect diameter was found, the grip could be printed, knowing that it would work. If the plastic was not prone to shrinking, this would be an easy task, but now we had to test and try our way to the perfect fit.

Img 0812
Some of the test rings.
Img 0810
The final solution for griper interface for robot and screwdriver.

Finished product

But even with proper testing and measuring, things do not always work on the first try. During the development of the new factory, we faced many different problems.

One example is the holders for the screwdrivers. These were not only docks for the screwdrivers, they also had to be strong enough to hold the screwdrivers in place during transport. Once we were finished with the design, we started testing the strength of the holder.

Hallare Skruvdragare
Testing the holder, the broken holder and the final solution for holding the screwdriver.

We also had problems with strength making the fingers for the robot. They always broke when they were used. We could not change the design of the fingers, so we had to find another solution. After a while we figured that the parts were very weak in the direction pointing upwards in the 3D printer. Since the 3D printer builds the detail in horizontal layers, this direction is strong. However, the hold between the layers is weak, and this causes the detail to be weak in the vertical direction. We printed the finger on the side instead and increased the infill to 80% and it never broke again.

Robot Fingers
The fingers on the left and right arm of the robot.
Finger På Platta
Print the fingers like in the second picture, not like in the first picture. This gives the fingers more strength.

During the designing of the boxes for the springs and bolts we faced yet another problem. The bottom plate always seemed to get offset from the rest of the box. After a conversation with ZYYX we found out that this was caused by the software we used to slice the CAD models. When the angle between the ground and the box is too small, the software tends to miscalculate the amount of support material needed. This causes the extruder to get stuck and miscalculate where it is witch can then cause the box to be offset from the bottom plate.

Lada
The angle between the box and the ground is too small. The blue arrow is pointing at the place where the box got offset.
Skruv Och Fjäderåda Gamal Och Ny Konstruktion
The problem was solved through a redesign of the box. The small angle was replaced by a flat surface.

Author: Anna Andersson, Göteborgsregionens Tekniska Gymnasium (2019)


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Artikeln är kategoriserat som Fördjupning  /  Publicerad 2019-03-10  /  Skriven av johan