Our project:
Aerofoam

Project description

We need to come up with an idea so that we can automate the assembly of the foam pieces. The problem is the difficult shape of the pieces and the glue that is still applied manually.

Research

The foam
NBR isolation material is an abbreviation for nitrile butadiene rubber. It is used for insulating freezing and cooling systems. This means that the rubber can’t be heated to melt the pieces together.The foam is also an elastomer that is very elastic. This means that the glue used to glue the pieces together should not be elastic.

The glue
Walraven has already done a number of tests to determine which glue is best to use. Using the ISOFIT glue master with the Kaiflex 414 glue ensures that the foam adheres well to each other. Spraying the glue means the adhesion is not good enough and gluing by hand is too slow. It is now up to us to find a good solution.

The process now

The glueing
Gluing is now done manually with a brush on the bottle. About 8 pieces are glued at the same time. Glue is required on 2 sides per piece. We have to find a way to glue as many pieces as possible in one go and that the glue adheres well enough to the foam.

The assembly

Step 1:
They use 2 molds to bend the foam. The outer bend is used for the long sides and the inner bend for the short sides.

Step 2:
They place the foam on top of each other and thus glue the sides. An adhesive distributor is used where the brush makes good contact with the foam

Step 3:
After gluing the sides, they are placed on the mold. Here they are pressed firmly against each other so that a good connection is created.

Problems

Production takes too much time
The manual labor is too taxing
The foam pieces have a difficult shape, making the assembly very complicated
The foam pieces have a difficult shape, making the gluing very complicated
Mass production is not possible
The factory requires a lot of people to assemble the end product if you want to make more than just one piece at the time.

Improvement in gluing

Instead of using a brush you can use rollers. The rollers must either be supplied with glue every second via a small slide. What you can also do is immerse the rolls in a container full of glue, but this option takes more time and isn’t as successful as the other small slide option.

Rollers in a container with glue

The roller moves into a barrel with an up and down movement. The barrel contains the glue that must be sealed off from oxygen. So the container must be closed. Our idea was to place a plastic layer on the entrance of the barrel that was just large enough for the roller to pass through. Because the glue is not completely sealed, this is not the most ideal solution, but it is better than gluing everything manually.

The roller must be able to rotate while the foam pieces pass in a specially made rail attached to the roller. The roller should not turn too fast so that the glue is properly absorbed by the foam pieces. You can adjust the roller to the amount of foam pieces you want to place on top of each other.

Rollers with a small slide

The glue stored in a sealed space can be transported to the roller via a line controlled by a filter. By controlling the filter you can determine the amount of glue. The roller must be adjusted so that there is a small vessel inside the roller from which the glue comes.The roller must be able to rotate while the foam pieces pass in a specially made rail attached to the roller. The roller should not turn too fast so that the glue is properly absorbed by the foam pieces. You can adjust the roller to the amount of foam pieces you want to place on top of each other.

Improvement assembly

We also had an idea to work with exterior and interior molds. These should ensure that pushing the two pieces against each other no longer has to be done by hand. This can then be done mechanically/pneumatically. This is the most realistic idea.

Using molds

The principle of this idea is that there is an outside mold in which you place your shapes. The inner mold (the final shape) is then placed in it. The outer mold is closed. This can be done mechanically or pneumatically. The force will ensure that the foam can adhere properly. The intention is to make different tools (sizes) for the different foam shapes and sizes.

Using rollers pushing the foam together

There are 4 gates attached onto a round rail. The ports themselves consist of a valve controlled contact that is either open or closed so that the pieces remain secured or released. The gates can be controlled so that pairs of 2 can fit exactly against each other. First the 2 ports assemble the small sides of the foam pieces. The others are brought together so that the foam pieces are assembled on the tube.

Our self-conducted research

Step 1: Collect material
We ensure that all our material is ready so that we can start immediately.
Supplies:
- 2 foam pieces
- the glue
- the adhesive distributor
- the mold to hold the foam in place
- the tube

Step 2: Assemble mold
Finding the right mold to lay the foam in. Then we assembled the green parts in the right place.

Step 3: Mixing the glue
We opened the glue and stirred it for a moment. After stirring it, we poured it into the glue dispenser.

Step 4: Gluing
We had to pump to get glue out of the glue dispenser and then we could get started. We spread the glue over the foam with the brush attached to the head. The glue is fairly liquid, so you have to be careful that everything doesn't drip down.

Step 5: Drying
After gluing we need to let the glue soak for 3 minutes. This ensures better adhesion. When Zinaida let her pieces dry I already started gluing my pieces. So we had a kind of assembly line.

Step 6: Assembling
First we started by pressing the top of the long side. Then we worked towards the bottom. Once the long side was done we did the same for the short side.

Our experiences:
- It has to be right the first time --> you can't pull it loose again
- Press well

Step 7: Let it dry
After gluing we have to dry it so that the foam adheres well. Once it is dry you can no longer pull it apart. We have found that if you use too little glue you can still pull it apart.

Final conclusion

We would use the Rollers with a small slide assembly and the exterior and interior molds assembly. These are the most realistic ideas and the most future-oriented. The other ideas are more of a short-term solution. Below you can see how 2 complete machines could be used side by side. The machines would still have to be used separately. It can be 1 machine, but then it becomes a very complicated drawing. This is the end product that we send to the company to automate the gluing and assembling the foam pieces.

End of the project

After 10 days of work the project is completely finished. We worked from 8 a.m. to 2 p.m. In addition to time for designing and inventing, we also spent time on testing and meetings. We are very happy that we have completed the project so that the people of Walraven can continue to build on it.

Kind regards Nina

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Our project:Aerofoam