Rebuliding of a cutting- and bending machine

This thesis work has been performed on request by SWT (Scandinavia WeldTech AB). SWT manufactures, develop and sell ready to assemble building systems for concrete rafter beam applications. The beams in this system consist of a u-beam that is welded to a flange. To be able to fill the beams with concrete there is holes in the beams top end. The holes are made in a “punching machine”. These holes are cut out and the remaining steel piece is bent down in the u-beam. The problem today is that the machine only can make holes in beams with a height up to 340 mm. Now SWT wants a machine that can handle beams up to 500 mm high. Our task in this work was to make a feasibility study on what needs to be done to rebuild the machine. Besides the demand with higher beams we also looked at things to improve. Another task was to investigate the needs for cutting in beams made by thicker steel plates. In this work we used some of the theories described by David G. Ullman for the concept generation and evaluation. When generating the concepts we choose to make a concept of each subpart of the machine. Then we put the winning concepts together to form a final solution for the whole machine. When looking at the wear on the tools we could see that much could be done by making the control of the cutting column easier when adjusting the tool. To see what demands there were for cutting in thicker plates we had to come up with a theory for calculation off cutting and bending. Then we had to compare our theory with the reality, and that was done by measuring the pressure on the working cylinder when the machine was operating. Those results showed that our theory was working for 5 mm thickness but not for 4 mm thickness. There is however some uncertainness that makes our measured results not quite reliable for 4 mm steel. When it comes to the demand to manage higher beams we came to the conclusion that the best alternative is to manufacture a new frame. This is also suggested for the plates in the feeding unit. But we recommend that the existing cylinders and roof is used. For the problem on how to make the tool adjustments easier we came up with two solutions. The alternative with manual adjusting and assembly demands a reconstruction of the hydraulic system so that its functions meets the demands that are needed to realize the proposed solution. The advantage with this proposition is that the operator always has the possibility to affect the position of the tools so that the right cutting column is received. Our other suggestion is to install permanent steering guiding so the lower die gets in right position when mounting it. This proposal does not mean any bigger reconstruction but it does not make it possible to adjust the position of the cutting tool. To work proper both our solutions demands that the lower dies is modified. To make the mounting of the upper die easier we came up with two solutions that in short terms means that the die is held up before mounting. This means that the operator can have both his hands free when tighten the bolts. If thicker plate should be cut it will lead to large reconstructions of the hydraulic system with new cylinders and more. This due to the maximum pressing force that the machine is capable of is too small. But for a small change in thickness it might be enough to lower the force by reducing the friction in terms of better lubrication and modified tools