The Spice Must Flow with servomotors

I recently installed a couple iHSV42-40-07-24 servo motors in The Spice Must Flow corexy sand table. It took a little messing around to get them running, but once I did, I started trying to test their limits.

Here's a video of the mechanism running with acceleration set to 10,000 mm/sec^2 and speed set to 2000 mm/sec:

[vimeo.com]

That's without tweaking the motor parameters in the integrated drivers.

The mechanism is running at 31.25 steps per mm, so the Duet board should be able to drive it up to about 6400 mm/sec.

It will never be able to run this fast with sand on the table, and it makes more noise at these settings than is acceptable, but it's very quiet at reduced speed/acceleration that can actually be used to draw in sand.

I'll be trying these motors out in UMMD eventually.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I turned the table on its side, put a coin cell battery and LED in the magnet carriage, propped open the camera shutter, and ran a pattern. The result:



At the corners of the pattern, where the mechanism has to slow down, the light looks brighter than in the areas where is was screaming along at much higher speeds. It's a nice effect.

The very high speed of the mechanism allowed this pattern to be drawn in about 5 minutes, considerably faster than it could be drawn in sand. The LED is much smaller than a line in the sand would be, so it should be possible to make some very finely detailed patterns this way. More experimentation to follow...

The speed was set to 1500 mm/sec, acceleration 10k, and jerk 200 mm/sec. The stray light on the left side of the image is from the LEDs in the power supplies, controller board, and motors.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... could be an eye-catcher too with an UV light (LED or laserdiode) on a fluorescence sheet

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I was thinking the same thing...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... see here for some examples:

[www.youtube.com]

[www.youtube.com]

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I think the rustoleum paint uses zinc sulphide as the glow medium. The good stuff is strontium aluminate which glows brighter and for much longer- maybe better suited to a machine that takes a few minutes to draw a complete pattern.

Like this: [www.amazon.com]

I'll get a small sample of it and try it out...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I put the sandbox back on the frame last night and ran some tests with different patterns. I discovered that with servomotors, the table can actually run patterns at 10k mm/sec^2 acceleration (previous testing with steppers limited acceleration to 2k because the steppers would stall out at higher settings) and the magnet still hangs onto the ball. Almost all the line segments in the pattern, even short ones, manage to hit 500 mm/sec with the acceleration set that high. At 10k the ball tends to throw the sand around, so high acceleration isn't for patterns with a lot of fine detail. It is great for erase patterns! With the sandbox on the frame, the mechanism is much quieter, except I still need to spring load the Y axis bearings to keep the X axis from shifting and making a clunking noise when the magnet carriage reverses direction. That clunking is now the loudest noise source. The pulleys I made from F625 bearings run much quieter than the 3D printer pulleys with tiny bearings that they replaced. The servomotors are also quieter than the steppers were.

I'm using sandify to generate patterns and it allows custom gcode to be entered at the start and end of each pattern when you export it. I put homing, speed, acceleration, and jerk settings in the custom start gcode and an M84 (disable motors) at the custom ending gcode. The M84 at the end stops the whining noises that the motors tend to make when they are sitting still.

I am working on a new design for the Y axis bearing blocks that will solve the clunking noise problem. The extra friction that results from spring loading the bearings won't be a problem with the servomotors.

With the steppers, I was operating right at the limits of what they could do, which meant that every change to the mechanism potentially had an impact on the speed/acceleration limit of the mechanism. With the servomotors, I no longer have to worry about that. They will take anything I throw at them and keep the mechanism moving faster and at higher acceleration than I will ever need for drawing the patterns.

I'll post some video, shortly.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

As promised, I put the sandbox back on the table and ran some patterns. Here's a test in which I was attempting to find the upper limits of speed and acceleration. I haven't found them yet!

https://vimeo.com/423704831

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... it's a beast of a sand-table!

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

You could try something like this [www.youtube.com] if you like to.