CAD?

[cxcad]

Communication with the build team is key. Otherwise, there will be two very different robots, one physical and one virtual.

[artdutra04]

Develop a system for part numbers and revisions and stick to it.

Never use names like Intake Left Arm Outer Side Plate 2.sldprt as this makes it very difficult for BOM and PDF drawings when you send parts to sponsor machine shops. Names like 2014-110-001_Rev1.sldprt or 2014-110_Rev8.sldasm are much better and better prepare you for how companies in the real world work.

Don't be sloppy on your modeling. Constrain ever sketch entity - if you open a Solidworks sketch there must never be any blue lines.

Don't use project/convert geometry from an assembly into a part. It's great and fast when it works the first time but when you iterate and change designs it will be a minefield of broken references that will take for ever to fix.

[Dival]

Originally Posted by artdutra04

Develop a system for part numbers and revisions and stick to it.

Never use names like Intake Left Arm Outer Side Plate 2.sldprt as this makes it very difficult for BOM and PDF drawings when you send parts to sponsor machine shops. Names like 2014-110-001_Rev1.sldprt or 2014-110_Rev8.sldasm are much better and better prepare you for how companies in the real world work.

Don't be sloppy on your modeling. Constrain ever sketch entity - if you open a Solidworks sketch there must never be any blue lines.

Don't use project/convert geometry from an assembly into a part. It's great and fast when it works the first time but when you iterate and change designs it will be a minefield of broken references that will take for ever to fix.

We had this issue this year. Can you explain a bit more about how you organize the part numbers so that the team can handle them?

[Marc S.]

If you are starting fresh, I would recommend trying out Solidworks. I like it better than Inventor and, at least where I live, there's a lot more real world demand for it.

Look online for tutorials. Many FRC teams have put up FRC specific cad tutorials that are very helpful (973 RAMP being the first one to come to mind).

Another thing to keep in mind, is that a team sould never restrict students to just the "CAD team". Make sure that the people deciding how "it" fits together have experience putting "it" together. The best practice you can get is sitting down with your machinists/builders (they don't necessarily have to be the ones cadding but it will benefit you if they know how) and design and build a prototype robot in the off - season. Anyone can put up a CAD image on cd, it takes skill to design a robot effectively with your resources in mind. Doing it in the off season lets you learn from your mistakes with out hurting your team's productivity.

If you have any solidworks specific questions feel free to pm me, and of course others who post cad specific details on cheif.

[artdutra04]

Originally Posted by Dival

We had this issue this year. Can you explain a bit more about how you organize the part numbers so that the team can handle them?

I used a similar standard when I was on 228 as we currently use on 148: YEAR-SUB_SYSTEM-PART_ID. The top level assembly is 000, and each major subsystem gets a number like 100 for drive train, 200 for mechanism 1, 300 for mechanism 2, etc. Sub assemblies within that mechanism get numbers like 110 or 320. Each individual part is assigned a unique ID in the lowest assembly it is used in. If parts are COTS, you use the the manufacturer part number.

2014-000 Rev1 (main robot assembly)
- 2014-100 Rev1 (entire drivetrain assembly)
-- 2014-100-001 Rev1 (drive train part 1)
-- 2014-100-002 Rev1 (drive train part 2)
-- 2014-110 Rev1 (gearbox)
--- 2014-110-001 (gearbox part 1)
--- McMaster 91251A342 (#10-32 x 0.5in SHCS)
- 2014-200 Rev1 (mechanism 1 assembly)
-- 2014-200-001 Rev1 (mechanism 1 part 1)
etc

This is also really useful because in Solidworks you can set who has write access and who has read-only access, so you can have multiple people working on the CAD at once (one person could be editing -100 assembly and sub parts, another editing -200 assembly and sub parts, etc). The key to making all of that work is by opening all referenced parts as read only. To do that, check this box:

[Jay O'Donnell]

Take the summer to CAD something like last years robot or a battery cart or something like that, it really helped me to prepare for Build Season this year. You also don't necessarily want too much of a good thing, I've found that more than a few people working on one CAD can get to be tricky if you're not all on the exact same page. Also please save to multiple places, you don't want to lose all that work. Good luck with CAD!

[alexander.h]

Is there any link whatsoever between the programming language we use on our robot and the CAD software we might use to model it?

[Joe195]

Originally Posted by alexander.h

Is there any link whatsoever between the programming language we use on our robot and the CAD software we might use to model it?

Not at all. They are separate programs and there is no connection. The type of software your team uses really depends on prior experience.

[alexander.h]

Originally Posted by Joe195

Not at all. They are separate programs and there is no connection. The type of software your team uses really depends on prior experience.

Thanks!

[jamierose]

Along with what everyone else said, I suggest taking a look at this Design and CAD guide made by another student on 610. This was written by someone who had no idea how to CAD at the beginning of Grade 9, so it might be quite accessible to newer users.

http://www.chiefdelphi.com/forums/sh...d.php?t=125208

Designing mechanisms for robots is part of the curriculum of every Grade 9 in the school, so virtually everyone on the team knows how to design a part in SolidWorks and then make it in real life. Due to this, I can confidently say that almost every single student on the team now is better at designing in SolidWorks than our head of Manufacturing/Mechanical than when I was in Grade 9 and it was separate from the CAD division.

Basically, I suggest that the people who build the robot and the people who design it using CAD software learn the other skill eventually, as it makes everything so much easier.


We also have more basic CAD tutorials for the Grade 9 technology course at my school. I'll see if we can post them online.

[Michael Hill]

Another thing to do in the off season is to make COTS parts in Solidworks (or whatever your team decides to use) your team uses a lot. It will save you time during the season. You can adjust the masses of certain items and even apply materials to make the look better for a render if you choose...stuff you shouldn't waste time on during the season that costs nothing to do now. I'd suggest CADing up a drive base or two in the off season. Not only will it make you more proficient in CAD, but it can provide some insight on drive base design that will help during the season (common pitfalls, difficult to CAD parts, etc.).

[John Retkowski]

Originally Posted by Michael Hill

Another thing to do in the off season is to make COTS parts in Solidworks (or whatever your team decides to use) your team uses a lot. It will save you time during the season. You can adjust the masses of certain items and even apply materials to make the look better for a render if you choose...stuff you shouldn't waste time on during the season that costs nothing to do now. I'd suggest CADing up a drive base or two in the off season. Not only will it make you more proficient in CAD, but it can provide some insight on drive base design that will help during the season (common pitfalls, difficult to CAD parts, etc.).

^This exactly. One of the best ways to learn CAD is to start by making parts.
One of the things that helped our team was the Autodesk CAD guide which showed picture and measurements of increasingly difficult parts for us to make. Every time we hit a road block (which was very often in the beginning), we were able to learn a new way or tool to make us better. I remember the first part taking me an hour and a half to make. But through the knowledge I've gained I could make that same part in five minutes. Making parts for your bot is an especially efficient way to not only accumulate experience, but also to give you a head start in build season.

[Oblarg]

Originally Posted by artdutra04

Don't use project/convert geometry from an assembly into a part. It's great and fast when it works the first time but when you iterate and change designs it will be a minefield of broken references that will take for ever to fix.

Honestly, this ties into the "constrain everything" practice, and while I agree it's an ideal to strive towards, it's not always feasible.

Certainly, any sketch you construct from scratch should be fully constrained, but there comes a point (complex mounting patterns transferred from .STEP files that you had to get from the internet, for example) where constraining everything will do nothing but give you a headache. Any time you need to incorporate geometry that you yourself did not actually design, you're going to run into this. It seems clear to me that the best solution is not to re-create all of the geometry from scratch.

Fortunately, those aren't things that you tend to make iterative changes to, as they're not something that you are actually designing, so you're not going to lose much by being "sloppy" there.