"FRC BOM Collection" and "BOM Stories and Tips Collection"

FIRST General Forum
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There have been countless discussions about the BOM but as a community, we have very little data. Hopefully, as we enter into the competition season you will help us change that.

Please reach out to teams you know and ask them to submit their BOM as well. The more we collect the more complete of a picture we can see about how the BOMs are actually being completed. Spreadsheets are great but pictures work as well, take a photo of the piece of paper that you hurridly created the BOM on at an event and upload that to Imgur and submit the link.

FRC BOM Collection

Spectrum and I are creating a collection of Bill of Materials(BOMs) from as many teams as possible. We will be releasing them publicly, you can choose to do so anonymously or not.

Thank you for helping us get a better understanding of how the BOM is completed by various teams.

BOM Stories and Tips Collection

We also want to document how the BOM has effected teams and ways that teams have found to account for their robot costs to keep them under the limit.


Spectrum and I are also creating a collection of Bill of Materials Stories and Tips. Some examples of what we are looking for are below but really we just want to know how the BOM has effected your team over the past 2 years (2019 and 2020), any feedback is welcome. The responses will be public(after review), so your team number is optional. If you have things you don’t want to be public feel free to send an email to [email protected]

Any BOM related tips or stories are welcome.

Some suggested prompts for stories.

  • What have you done to get in compliance with the FRC BOM rules?
  • Has the BOM been a benefit or a detriment to your team?
  • Do you have any suggestions for how other teams can reduce their accountable total?
  • How has the BOM inspired your students or improved your team?

Example Stories (the more details the better)

  • “We had to remove our limelight as it would have put us over the BOM”
  • “We bought 88 pool noodles so they are under $5 each instead of just the 12 we needed.”
  • “We swapped all the aluminum pulleys we already owned to 3D printed ones to reduce our BOM total”
  • “We purchased motors we didn’t need with a voucher so we could exempt them from our BOM”
  • “We spent over 10 hours looking for IFR pneumatic cylinder prices from international sites to get our total under”

Example Tips, the more specific the better

  • Useful website links for IFR items at low prices. (international sites, uncommon sites)(give direct links to products you used not just aliexpress, etc)
  • Items that can be purchased in bulk to reduce their BOM cost.
  • Useful exempt items(under $5)
  • Items that you make instead of using a COTS part that has to be accounted for as more.
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Are you collecting BOMs for this year only?

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2019 and 2020. Anything prior to that were under dramatically different rules.

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Nothing too crazy so far in our 2020 BOM.
http://team2363.org/2020/02/genome-mu-2020-bom/

I’ll submit these stories for now:

  • We spent ~$25 more than needed on a bulk purchase of shoulder screws (McMaster 91259A483) to bring the unit price down to <$5.

  • In total we actually spent ~$40 more than FMV on pneumatic cylinders to get the fast delivery time needed to keep pace with robot development.

  • We appreciate the enormous continued support of our sponsors and stakeholders. Fielding this year’s $4,411 robot was made possible by approximately $11,047 in FY19-20 spending on robot parts.

Thanks Allen and Spectrum for collecting these BOMs!

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We are using a recycled field piece from the FTC field. I was afraid that I would have to list the entire field kit (which, fortunately, is under $500), just to use one plastic pipe! Or spend hours looking for an IFR somewhere (I don’t even know what type of plastic it is; we had been using PVC but our team wanted the colored one from the field for aesthetic reasons).

Fortunately, I checked AndyMark and they do sell that pipe for $3.50. Phew! But what if we had wanted to use a different piece from that field for something?

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Years ago I got into the mindset of “the robot only gets parts that we can buy”, when designing and working on FRC robots. The rules used to be a bit tougher than they are now, in some ways. In other ways, it’s tougher now.

First go at our BOM this year, with all the pneumatics, etc accounted for, total BOM is just over $1800. Kind of expensive. And I might have missed some motor controllers, etc. Will submit when it’s done. (we’ve had BOMs in the $400 range in the past)

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With teams going to their week 1 events, I’d love to see more teams submitting their BOMs to our collection.

Here is the BOM that Spectrum will likely be submitting at our event this weekend (unless we find something we forgot)

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4020 moved to COTS swerve this year, and it wreaked havoc on our BOM. We were sort of keeping up with costs as we went and tried to use vouchers efficiently, but when we got done with build and compiled the BOM, we were well over $5000.

Instead of focusing on the final touches to the robot for our week 1 competition, we spent the final week of build trying to figure out how to get our robot under the $5000 limit.

Many hours were spent trying to find the best prices for all of our bulk aluminum and plastic, both of which are donated to us by very generous sponsors. We also scoured BOM “tips” to find sources of parts for less than $5. One example is $4.99 30A breakers from VEX, which saved us a nice chunk of BOM cost. Using VBeltGuys for belts was huge for reducing the BOM as well as actual cost.

We also spent many hours trying to figure out how to piece together all of the material from fabricated parts into purchasable sizes of bulk material. In practice, we sometimes cut from “long” stock, but just as often we make parts from small off-cuts. We make prototypes and two bots so we really have no idea how much “raw” material we use. We have to go back and add up all the measurements and then group everything into purchasable sizes. This is especially “fun” when we make sure we can nest sheet parts into purchasable quantities. We’d never put all the Inventables 1 sq. ft. aluminum sheets onto our CNC router and cut our parts out of those little chunks, but we can nest most of our sheet parts into 1 sq. ft. groups and use the Inventables voucher to deduct the cost of those parts.

We ended up rewiring the electronics and updating the programming, replacing four Talons with Victors, and replacing a network switch with one we got from FIRST Choice.

We had to remove one of our climb traverse motors and the associated gearbox, wiring and energy chain to get under the limit. We can still traverse with one motor (and did successfully at Palmetto), but we can’t climb a fully tilted generator switch with one motor.

We removed stages from some Versaplanetary gearboxes and rolled the dice with some 10:1 stages and slower motor speeds.

We changed out some lightweight pneumatic components for KoP components.

We removed some wheels from our intake and replaced with spacers.

We would have loved to put another motor on our shooter to minimize delays in recovering speed, but we can’t “afford” it.

In the end, vouchers and FIRST Choice helped us meet the BOM cost limit, but using these sources was a waste. We got some pneumatic solenoids and Spark MAX controllers from FIRST Choice that we already had, but by getting them again this year, we could deduct them from the BOM. We got aluminum sheet from Inventables which we did not need as we had sufficient sheet from a sponsor. Some of our AndyMark voucher was used for gears and other components we already had, but could now deduct. We would have loved to have a Bimba voucher again this year to be able to get cylinders we already had, but could have deducted. All our cylinders had to be accounted for this year.

We usually waste time on the BOM that could be used for direct robot work, but we’ve never had to literally be distracted for a week like we were this year. I don’t know how swerve teams produce some of the robots I see and stay within the BOM limits. Our robot is pretty complex, but not incredibly complex. We don’t use a Limelight, we don’t have any LIDAR on the bot this year, and we don’t have a sensored power cell magazine/conveyor.

Eliminating bag day this year seems to have been a rousing success that has been long requested and overdue. Perhaps we could see similar progressive thinking substantially simplify any kind of cost accounting next year or soon.

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Here’s our BOM going into our first event this week. The freshman who put it together may have missed a small item or two, but nothing too significant*. It’s the first BOM we’ve had over $3000, driven primarily by the Falcon 500 and opting out of the KoP drive train.

2020 BOM - BOM.pdf (261.2 KB)

*First look through for me, she missed a Bosch Seat motor ($36) on our intake, and forgot to include the KoP drivetrain voucher we spent at AndyMark (-$400). That voucher alone probably makes up for anything she missed!

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Wait! You can use the vouchers to exclude parts?
We have some upkeep on our BOM to do…

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Now that the BOM is dead, @Nate_Laverdure, can you share the story about your golden shaft collar?

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Oh geez. OK. Gather round children.

In recent seasons, Ruland, a longtime FRC Gold Supplier and a manufacturer of precision shaft collars, has been running a lottery that’s packaged INSIDE the physical kickoff Kit of Parts. While every team received one of their nice aluminum shaft collars, a random subset of physical KOPs included a RARE gold-anodized shaft collar accompanied by a donation voucher for significantly more Ruland product.

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Ruland may have decided to end this product donation program, since they’ve deleted the webpage about it, although it’s still listed in the sitemap.
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It was quite a substantial donation! It appears that 100 teams recieved $100 in 2019 (6802 and 4292 are two examples), and 1389 received $500 in 2016. This is in addition to the huge amount of stock that the company donates to FIRST Choice every year! It is very admirable that they’re able to make such a great investment in FIRST teams.

In January 2019, there was a major shift in robot cost accounting rules which required every team in the league to work to a different robot parts & materials budget, determined by resource-allocation choices made throughout the year (both before and after the game reveal). More discussion on that here. The gist is this: robots could “cost” $5500 + the value of components that the team actually received in the physical and virtual KOPs.

Throughout fall 2018 and spring 2019, Triple Helix made a series of resource allocation decisions that priortized our growth and sustainability as a youth STEM organization over our competitiveness as an FRC entrant. For example, we spent our AndyMark PDV to outfit our newly-founded community STEM Gym with battery chargers. Because of this rule change for the 2019 season, we were unable to build the same robot as a hypothetical competitor who had used their credits, vouchers, and coupons to maximize their robot budget.

However, when we finally opened our physical KOP on January 10, we learned that we were in luck… we recieved a golden shaft collar from Ruland!

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IMG_20190110_1737314048Ă—3036 1.77 MB

I buried this deep (slide 25) in my presentation on our 2019 BOM. We used the $100 donation to save $22 on our BOM cost.

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The presentation demonstrates the work we did to wrangle our BOM down below the $5500 limit, but we do acknowledge that there are plenty more things we could have done to shrink the accounted costs even further. (There were a number of good suggestions here by @wilsonmw04 and others.) However, all good things come to an end, and at the point we stopped working on our BOM , we found that were under-budget by $21.

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The Ruland golden shaft collar made our robot legal. If any of our 2019 competitors had made the exact same series of decisions over the course of the season and built an exact clone, you’d most likely be overbudget by $1.

Thanks FIRST for retiring the BOM.

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Can I get an amen?

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