3D Printing A Check Valve In Metal

[SunShine] has been working on 3D printed pumps and similar parts with an aim towards building smaller and more compact hydraulic systems. His latest effort involves printing working hydraulic check valves that can be integrated seamlessly into his designs. 

Unlike many 3D printing enthusiasts, [SunShine] works with metal printers of the laser powder bed type. His expectations for his parts are thus very high, and he aimed to create check valves that could withstand high hydraulic pressures.

After much work, [SunShine] came up with two designs for 3D-printed check valves that would work. However, they both needed internal removal of support structures that couldn’t be achieved without cutting them open. He then figured out that he could use a special process using nitric acid to carefully eat away a very precise amount of metal inside the valves, which would remove the support material without destroying the whole valve itself.

While the valves couldn’t be tested beyond 400 bar due to the available equipment, they did work as intended. As a bonus, they actually sealed better as they were used more, as the sealing surfaces bedded in and deformed to match each other.

The video is then rounded out with a simple plastic check valve design you can print at home. It reminds us of other valves we’ve seen created with 3D printing before. Video after the break.

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How To Convert An Internal Combustion Engine To Run From Steam Power

We had no idea that what’s needed to convert an internal combustion engine to steam power is actually rather trivial. [David Nash] shows us how it’s done by performing the alterations on the engine of a string trimmer. These are the tools used to cut down vegetation around obstacles in your yard. The source of the engine doesn’t really matter as long as it’s a 2-cycle motor.

This engine had one spark plug which is threaded into the top of the block. [David] removed this and attached his replacement hardware. For now he’s using compressed air for development, but will connected the final version to a boiler.

There are only a couple of important parts between the engine and the boiler. There’s an in-line oil reservoir to help combat the corrosive nature of the steam. There is also a check valve. In the video after the break [David] shows the hunk of a ball-point pen that he uses to actuate the check valve. It’s really just a spacer that the piston pushes up to open the valve. This will be replaced with a metal rod in the final version.

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[Matt’s] Bubble Display Updated

[Matt] emailed in to show us how he has improved his bubble display since the last time we saw it. If you recall from last time, he was having issues with the air pressure dropping when multiple bubbles were released, resulting in smaller bubbles. This time around, he has added an aesthetically pleasing air reservoir to help ensure that his bubbles don’t vary too much. There really wasn’t a reason to use two containers for the reservoir, aside from the fact it is what he had on hand. He has also torn part the part of the display that houses the oil, replacing it with individual tubes for each vertical segment. This makes it easier to regulate the speed of the bubbles, as he found they travel at a constant rate if they are in contact with the edges of the tube.

One downfall of using the vinyl tubes is the fact that it comes in a giant roll. This leaves the tube wanting to curl. To get around this, he stretched it on a wooden dowel and heated it with a heat gun till it relaxed. Using clear PVC or acrylic tubing would be an alternative but would be more expensive.

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