Sunday, March 17, 2013

Nailed an Interfaced Part on the First Try

If you have been working in 3D printing with an extrusion type of printer... including very expensive ones... you will know that one of the historic issues has been the fidelity of the printed output relative to the design specifications.

I had been extremely busy with a very complex design of a system that requires tight interaction with many different parts.  Receiving a 2nd Gen Cube was a bit of a mixed blessing.  On the one hand, I realized that the 2nd Gen Cube has a high level of fidelity.  On the other hand, it meant a complete redesign to take advantage of this new accuracy.

I will be writing about the bigger project very soon.  But, for now I simply want to emphasize the accuracy of the 2nd Gen Cube by relating a smaller project that I'd been putting off for more than a month.

A friend had asked me to print a faceplate that fit into a case in which an electronic board would be mounted.  The part I was to create had to fit the opening of the case with perfect precision.

I am VERY pleased to report that using the design specifications supplied by the case manufacturer, it was extremely easy to match the new faceplate to the box.  In fact, the very first design worked!

That's pretty amazing to me.  I had been used to several iterations of modifying specifications to match real world measurements to the capabilities of a 3D printer.  The ONLY adjustment I made was to round all specifications to the next lower .25mm.

METRIC MEASUREMENTS HELP

I've abandoned using SAE measurements when designing for 3D printing.  All SAE measurements are converted to METRIC and the final designs are completed in metric.  The reason for this is that it is far easier to make precise adjustments in millimeters.

One reason for this is that the resolution of the printers are specified by their abilities to print in metric increments.  The Cube, for instance, prints in .25mm layers.  Thus, rounding down measurements to the nearest .25mm Z-Axis increment ensures precise height specifications.  Likewise, even with the 1st Gen Cube, we knew that the nozzle extruded a .50mm strand of filament. So, we could make adjustments once we had enough experience with matching design specs to printed reality.

I'm not exactly sure if the X and Y movements are locked in to .25mm increments.  But, if we start with that assumption, we can use small .1mm experiments to check out that theory.

ACCURACY REDUCES ITERATIONS

Lastly, I want to say how much I appreciate the efforts of the Cube design team to address the accuracy issue with the new 2nd Gen Cube design.  It has vastly reduced the iterations required to reach a final design.   NICE!

1 comment:

  1. Hi Tom,

    You say:

    "That's pretty amazing to me. I had been used to several iterations of modifying specifications to match real world measurements to the capabilities of a 3D printer. The ONLY adjustment I made was to round all specifications to the next lower .25mm."

    I'm not exactly sure what this means. Does this mean you reduce a 30mm length to 25mm or to 5mm?

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