Stress test

3 Articles

It’s A Bench, But It’s Not Benchy

January 12, 2025 by 27 Comments

Whatever the nuances are surrounding the reported taking down of remixes derived from the famous Benchy 3D printer stress test, it was inevitable that in its aftermath there would be competing stress tests appear under more permissive licensing. And so it has come to pass, in the form of [Depep1]’s Boaty, a model that’s not a boat, but a bench. Sadly this is being written away from a 3D printer so we can’t try it, but we can immediately see that its low bed contact area from having spindly legs would be a significant test for many printers’ bed adhesion, and it has overhangs and bridges aplenty.

It’s always interesting to see new takes on a printer stress test, after all we can all use something to check the health of our machines. But the Benchy saga isn’t something we think should drive you away from the little boat we know and love, as it remains an open-source model as it always has been. We don’t know the exact reasons why the derivatives were removed, but we understand from Internet scuttlebut that the waters may be a little more cloudy than at first supposed. If there’s any moral at all to the story, it lies in reading and understanding open source licences, rather than just assuming they all allow us to do anything we want.

Meanwhile it’s likely this model will be joined by others, and we welcome that. After all, innovation should be part of what open source does.

Missed the Benchy takedown story? Catch up here.

Thanks [Jeremy G] for the tip.

The 3D Printed Car Tire Rim Finally Hits The Road, Sorta

March 7, 2022 by 21 Comments

When you think of “car rim” you probably think stamped steel or machined alloy with a sturdy drum to withstand the arduous life of the road, not something 3D printed out of ABS. That would be crazy, right? Not to [Jón Schone] from Proper Printing, who’s recently released an update about his long-term quest to outfit his older sedan with extruded rims.

There were a few initial attempts that didn’t go as well as hoped. The main issue was layer separation as the air pressure would stretch the piece out, forming bubbles. He increased the thickness to the absolute maximum he could. A quick 3D scan of the brake caliper gave him a precise model to make sure he didn’t go too far. He also couldn’t make the rim any bigger to fit a bigger wheel to clear the caliper, as he was already maxing out his impressive 420 mm build volume from his modified Creality printer.

A helpful commenter had suggested using a threaded rod going all the way through the print as a sort of rebar. After initially discounting the idea as the thickness of the rim gets really thin to accommodate the caliper, [Jón] realized that he could bend the rods and attach the two halves that way. Armed with a paper diagram, he cut and bent the rods, inserting them into the new prints. It’s an impressive amount of filament, 2.7 kg of ABS just for one-half of the rim.

It didn’t explode while they inflated the tire and it didn’t explode while they did their best to abuse it in the small alley they had selected for testing. The car was technically no longer road legal, so we appreciate their caution in testing in other locations. In a triumphant but anti-climatic ending, the rim held up to all the abuse they threw at it.

We’ve been following this project for several months now, and are happy to see [Jón] finally bring this one across the finish line. It sounds like there’s still some testing to be done, but on the whole, we’d call the experiment a resounding success.

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HALT In The Name Of Testing

July 1, 2016 by 16 Comments

“Did I forget something?” It’s that nagging feeling every engineer has when their project is about to be deployed – it may be a product about to be ramped into production, a low volume product, or even a one off like a microsatellite. If you have the time and a few prototypes to spare though, there are ways to alleviate these worries. The key is a test method which has been used in aerospace, military, and other industries for years – Highly Accelerated Life Testing (HALT).

How to HALT

The idea behind HALT testing can be summed up in a couple of sentences:

  • Beat your product to death.
  • Figure out what broke.
  • Fix it, and fix the design.
  • Repeat.

Sounds barbaric, and in many cases it is. HALT testing is often associated with giant test chambers which are literally designed to torture anything inside them. Liquid nitrogen shock cools the chamber as low as -100°C. The Device Under Test (DUT) can soak at that temperature for hours. Powerful heaters then blast the chamber, causing temperature rises of up to 90°C per minute, topping off at up to 200°C. Pneumatic hammers beat on the chamber table causing vibrations at up to 90 Grms and 10 KHz. Corrosive sprays simulate years of rain and humidity. These chambers are literally hell on earth for any device unlucky enough to be placed inside them. It’s easy to see why this sort of testing is often referred to as “Shake and Bake”.

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