Re: Re: More travel protection???


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Posted by Jim Andrada on November 07, 2001 at 14:32:14:

In Reply to: Re: More travel protection??? posted by Rick Denney on November 07, 2001 at 11:58:50:

Lots of good ideas about foam, but I think there needs to be some caution (ie a little "package design") applied.

I haven't had a lot of experience shipping tubas, but we've been shipping high precision mechanical assemblies (+/- 5 micron tolerance) across the Pacific and have learned a lot about foam inserts. We found that if we didn't "chamfer" the corners of the foam blocks about an inch or so and also relieve the end surfaces somewhat so that there were strategically placed air spaces that allowed the air space to act like a "crush zone", there was high susceptibility to corner impacts transferring enough shock to the product through the foam to not only ruin the calibration, but to actually bend the sheet metal.

I suspect the two extremes would be to cast the horn into a block of concrete (:-)) or suspend it in the middle of a steel case with flexible straps.

I think the idea is to provide a flexible enough medium between the case walls and the instrument to allow the horn to experience lower G forces than the case itself - this requires that it be able to move somewhat relative to the case, and also you need to be careful to ensure that impacts don't actually transmit high "bending" stresses to the horn as the foam packaging deforms.

There's no substitute for a good packaging engineer plus drop and vibration testing, but this is impractical if you're shipping stuff "one off". You'd probably have to destroy a couple of horns before you got it right :-) I'd be pretty sure that higher volume manufacturers like Yamaha have actually done this.


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