In the last post, we showed the CAD model on Google sketch and had the CNC router machine to cut out the pieces. This blog post will discuss some problems we had during assembly.
Problem during assembly: Some parts were too big/small and wouldn't fit properly.
Solution: Use a file to cut fine amounts of material until it fits.
This was an issue because (1) we were unaware of the limitations of the CNC router (2) some holes were cut out too small. The CNC router uses a 2mm drill to cut out the pieces and this would set a limit on how small our holes/gaps may be. However this also meant that the corner of inner rectangular cut outs are rounded. We used a file to create those desired sharp edges.
The issue with the holes being too small was not the CNC machine's fault. For example, the CAD drawing specified 3mm holes and the holes came out exactly 3mm. The holes were meant for the 3mm diameter ABS material (the same filament used in 3D printing) however it was a very tight fit. The 3mm diameter ABS material had to be thinner such that it would easily fit inside the hole.
Problem during assembly: The work shop didn't have M2s long enough to hold 8 pieces of 2mm plastic pieces (screw must be longer than 16mm)
Solution: Ordered new M2 20mm plastic screws.
The solution above was very simple but we tried to work around this problem for 2 weeks! We tried some pretty dodgy ways to work around the problem by using shorter M2s found in the work shop but the finger was too fragile. In the end, we decided to order some 20mm M2 plastic screws.
Solution: Use a file to cut fine amounts of material until it fits.
This was an issue because (1) we were unaware of the limitations of the CNC router (2) some holes were cut out too small. The CNC router uses a 2mm drill to cut out the pieces and this would set a limit on how small our holes/gaps may be. However this also meant that the corner of inner rectangular cut outs are rounded. We used a file to create those desired sharp edges.
The issue with the holes being too small was not the CNC machine's fault. For example, the CAD drawing specified 3mm holes and the holes came out exactly 3mm. The holes were meant for the 3mm diameter ABS material (the same filament used in 3D printing) however it was a very tight fit. The 3mm diameter ABS material had to be thinner such that it would easily fit inside the hole.
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| Using a File we were able to make some changes. |
Problem during assembly: The work shop didn't have M2s long enough to hold 8 pieces of 2mm plastic pieces (screw must be longer than 16mm)
Solution: Ordered new M2 20mm plastic screws.
The solution above was very simple but we tried to work around this problem for 2 weeks! We tried some pretty dodgy ways to work around the problem by using shorter M2s found in the work shop but the finger was too fragile. In the end, we decided to order some 20mm M2 plastic screws.
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