V5RC Push Back Referee tool

[lacsap]

I made a quick and dirty model for robot inspection of string, plastic thickness, and zip ties in a 4"x8" packaging. Since STL generated using SketchUp for Schools, you should make sure print size is 4"x8".

RefTool-PushUp.stl (176.4 KB)

Look forward to seeing better designs

[lacsap]

Did a test print - and frankly, not good. Bigger is not better. In this design, the driving factor was the new plastic limit to 8"x4". Reality, this form factor is huge and is unwieldy for checking simple thickness of plastic, zip tie, or string on robot.

Moreover, I used PLA stock I had around, and let’s say pretty old. Results would not inspire confidence at inspection table

I will go back to simpler design for using on robot for gauging thickness of items, and use alternative for big items, like using 8"x4" cardstock for quick checks of plastic items on robot (dear RECF - maybe print these for EPs )

Well, design is a process, and missteps will happen.

[sazrocks]

For any kind of go/no go thickness gauge I recommend elevating the slot away from the build plate. If the slot is printed directly on the build plate then elephants foot is likely to change the dimensionality of the slot, varying especially with the kind of printer the part is printed on.

I have a couple small (and thus easy to fit inside crammed robots) go/no go gauges we’ve been using in AZ last season with good results, I’ll be posting them on the forum shortly.

[lacsap]

Ok - made a smaller version, and took @sazrocks advice for avoiding elephant foot. Being minimalist - no labeling of each slot - from left to right:

• String - 0.25"x0.25" slot
• Zip Tie 11" - 0.1875"x0.055" slot
• Zip Tie 4" - 0.1"x0.042" slot
• Double stacked plastic - 0.14"x0.14"
• Single plastic - 0.07"x0.14"
• V5RC PU logo

RefereeTool-Small.stl (4.6 KB)
(blank no logo)

[lacsap]

ugh - had wrong depth in model for 11" zip tie, rest ok.

Here is fixed model. length of block 3" - pretty portable.
RefTool-small-fixed.stl (4.6 KB)

[sazrocks]

Printed it and tested it out, a few items of feedback:

1. The slots are all a little bit undersized at their narrowest points when printed on my Bambulab P1S. For example I’m measuring 0.067” with my calipers on the single plastic sheet slot and 0.138” for the double stacked slot. I tested a piece of 0.07” plastic I had laying around and this made it fit pretty snugly into the slot rather than fitting in easily. I’d recommend adding a little bit of oversizing, maybe 0.005” or 0.01” to ensure legal items fit their slots.
2. You can probably get rid of the blank rectangular portion to the side of the slot, it would make the overall footprint smaller and easier to fit inside of robots.
3. To help identify which slot is which, you can add recessed lettering on the bottom face of the part underneath each slot to label them.

[lacsap]

thanks for feedback - minimalist design bring max improvement suggestions. The decorative rectangle could be removed, but my thinking at the time it fits inside my finger grip while checking inside robot. I will experiment a little more.

So, usability, your clearly defined tolerance of ± 0.01 makes sense if pro tool for head referee, but inspectors, I think you want them to hit edge cases and have a strong “this is gray zone”. giving too much wiggle room can lead to false positive by inspector, only to be called out by other teams (we have all been there).

That said, absolutely right - posting before thorough testing of design. I do think transparency is good and pointing out shortfall of tools used for 3D modeling and printing is important.

Full transparency:

• SketchUp for Schools is part of our district’s Google suite for all students to try 3D modeling
• Flashforge ADM5 is what I am using to print with Orca-flashforge slicer

In past, result ok-ish, but will need to validate this week with measuring tools to validate printed results.

If anyone is wondering why 3d printing is an issue, well consistency is it.