Hi, I’m the founder of my robotics team that plans to start its rookie year in 2016. We just got access to our local universities machine shop with:
My new mentors are wondering why would need all the machine shop equipment for. Could any give specific examples of what you would use each of these equipment for? If you could link pictures of specific parts made from a Mill or Lathe, that would be great too.
We use our lathe to make shafts for our custom gearboxes, intakes, and elevator roller assemblies this year. The lathe was only really necessary to cut the grooves for retaining rings. We used a mill to make our elevator rails (which we could have used a drill press for) and our intakes, which had weight reduction hole patterns and slots for the motor to mount to so it was easier to tension chain. I can upload pictures or CAD files of the parts later today.
Find mentors who know how to use the equipment - they’ll also know what it can and can’t be used for. The first place to look for mentors is right there at the machine shop - who runs the shop? Who uses it already? See if you can arrange some classes in using the equipment.
At an abstract level, with this sort of equipment and the knowledge of how to use it, you should be able to build components and subsystems and systems that fit together in clean, robust, and lightweight fashion. For many teams (my own included), match drilling pieces is sometimes the highest precision we can achieve.
Your biggest problem with all this equipment is likely to be the desire to use it just because you can - spending dozens or hundreds of hours on an item that’s not significantly better than a COTS item.
You’ll use these two a lot:
Drill Press
Band saw/cold saw
This is very useful, but many teams get by without it:
Lathe
Less useful, but many teams get by without it:
CNC mill
Not commonly used in my experience:
surface grinder (typically use a bench disc sander instead)
Does the CNC mill listed have a motorized rotary table or manual indexer?
There can be overlap with CNC capability between mills and lathes depending on how many accessories are on them.
For example live tooling and sub-spindles on a CNC lathe verus a vertical mill with a rotary table.
Alright, here’s what I’ve got:
CNC mills are beautiful for sheet metal fabrication, if you have someone who is willing to cad.
Lathes can be used to shave material off of axles/shafts that are too wide. They can also be used to tap or drill holes into axles/shafts.
Horizontal/vertical band saws are mainly used to make simple cuts (i.e… Cutting channel to length, making simple sheet metal/polycarbonate components, etc.)
Drill presses are good for making holes that don’t have to be very precise (prototype parts, for example)
Surface grinders can be used to remove sharp edges/burs from material that has been cut
Cold saws (from what I understand) are basically fancy chop saws, which can be used to cut material (channel, HDPE blocks) to length.
I like this point. Yes, it’s great to have these tools, but one has to justify whether it would be better to use COTS than custom-made. We have to consider more than just the cost of the materials – yes, custom broaching or milling or turning can save money, but you have to consider the “cost” of training your students to perform these tasks, the actual amount of time it takes to turn around one of these tasks, the time needed to make spares in case something breaks in competition, etc.
I’ve learned that there are many advantages of using COTS, and I intend to put a much larger focus on using COTS parts (including the KoP drive frame, if possible) next year to reduce build time.
Why would you use cnc mills for sheet metal fabrication? Cnc lasers/routers and water jets are way more suitable for sheet metal fabrication.
You’d rather use the cnc mill for stuff like tubing and solid milled parts.
Hi-
All those tools are very relevant during a FRC build season.
Specific examples;
Turning spacers for drive train use on a lathes seems to be the most common part we turn. We’ll also use the tail stock to drill and/or broach perfectly concentric holes; obviously a critical feature for rotating components. Yeah, there are other ways to do this, but the lathe is almost always the best tool for it.
We (team 95) will often use a CNC plasma cutter to ‘blank’ brackets and side plates, and a bridgeport style CNC mill to cut tighter tolerence features like bearing pockets, hole patterns etc.
the mill is also useful for making brackets in thicker materials; these parts (on the vice) were done on a manual mill, but could have just as easily been done on the CNC. They required a lot of material removal and a couple of loose tolerance fits. hogging that material out with hand drills, hack saws or making the parts out of several pieces would have been a huge pain.
CNC mills are great for repetitive parts. These bars were done on a CNC mill. Each feature had some tightish tolerances, and doing them all ‘by hand’ on a manual mill with DRO just wouldn’t be reasonable.
The other tooling, like bandsaws, drill presses and cold/chop saws are so basic in our build process that I don’t think we’ve bothered documenting their use much. They’re indispensable.
Take a look at the Robot Showcase sub-forum, in particular dig around for ‘build threads’, where teams detail the build process for their robots. They often have good photos and discussion of parts being made. All the photos I’ve used are from the Team 95 Hard at Work threads from the 2014/15 seasons.
What R.C. said - waterjet, laser, router all make more sense for sheet metal parts.
No - lathes are lathes. Mills are mills. There is some small overlap, but they do very different tasks.
No - you’re better off with a deburring tool or sander. Surface grinders are common in machine shops, but I struggle to think of where they would be necessary for FRC. They’re used to create very smooth, and flat surfaces - often at very tight tolerances.
They’re normally designed to cut ferrous material, normally at slow (<100 RPM) speeds. More or less a chop saw for steel or hard materials. Less than optimal for cutting aluminum, but they’ll work.
I am assuming that they don’t have a laser/water jet cutting sponsor and that they only have access to what they have in shop.
Lasers and waterjet cutters are not on the list of available machines.
Okay, now I realize my mistake… facepalms at my stupidity
I fixed my original comment.
Thats why RC recommended using the CNC mill for tubing and solid parts 
CONGRATS!! and thank you for starting a new team! It’s not easy to get sponsors with machine shop and have access to machines. I am sure many newer teams feel this pain.
All these machines are great, not just of robotics, for anyone who wants to pursue engineering. Some of our team members who have graduated have an advantage when they join college clubs, they breeze in the workshop training and a step ahead of the crowd in automation and building. Our team has the basic drill press, hand held power tools and small bandsaws and we are managing with them. Just think of a student who learns (or trained) on CNC? Its not what you can do with the machine to build a robot, its one’s imagination and perseverance to design and build something. I am sure students will find ways to use these machines.
I think the broader point that RC and Chris are making is that while a mill can perform precision cuts in sheet material, it is not the correct tool to do large scale “sheet metal” work in the conventional sense, and that with this resource set, a predominantly sheet metal robot would be a poor choice. The CNC mill works much better with a fabrication approach centered around extrusions, small gussets, thick, heavily pocketed plates, and complex parts milled from solid than a series of thin sheet parts, especially since you don’t mention having a precision brake to do bends either.
I understand that but in no way does a cnc mill beautifully makes sheet metal parts…
Also why would you recommend the cnc mill to make sheet metal parts if a brake isn’t on the list? I guess you can make just flat parts but at that point you might well just buy the gussets from vexpro or other vendors.
I feel the team here needs to understand what machines they got and how to combine their machining capabilities with cots components. We have both a cnc mill and router in house. We rarely produce true sheet metal parts (bent) due to the fact we can’t consistently bend the parts.
I would suggest you stay away from the surface grinder. They are used to make high precision flat surfaces, and they are easy to mess up if you don’t have proper training. Machine shops don’t like it when you mess up their machines.
On a related note, make sure you know exactly how to use these tools and get training before you use them. All of these tools have the potential to damage themselves and the operator if used incorrectly.
1st find a good junk yard.
You can make just about anything you need for FRC on those tools but you will need stock. Something you will be doing a lot in future will be to weigh time making custom parts vs buying them. If you can get good raw material for free (hence the junk yard) it cuts down on the material costs and assuming labor is free you end up with a ~free part. If you do get a good relationship with a junk yard you should get comfortable with using steel. It’s usually easier to find for free.
This goes into the main point that the more raw materials you can get donated from anywhere the more ~free parts you can make, especially simple things.
2nd get designing.
When you have custom capabilities like this it can be easier in the beginning to design things that are hard to assemble and sometimes impossible. The best way to avoid doing this in the middle of build season is to start practicing now. A good way to start may be to try to re-design your current robot with these tools in mind.
3rd Take a look.
Ask to sit in on the tools being used for as long as you can. It will give you a better understanding of what the limitations are and what kind of designs cost more time.
4th Ask an expert
First obviously the machinists who man the shop. But don’t forget the people designing things that get made in there. They will be a great resource in getting to know how to design for the tools.
Remember that the biggest cost to you will likely be time from now on if you can get donations.
Try to design things that don’t require the CNC. This I’ve found can help with machining time and will make you more resilient in case something you were depending on is not available right when you need it.
A better bet is probably to approach local metals and plastics distributors. Junk yards are unpredictable at best in what they’ll have, just do to their nature, and you generally won’t know too many specifics on the exact alloys you’ll be getting, important information for all parts of the fabrication process. Material distributors, on the other hand, are in the business of knowing exactly what their product is and how to use it. Look for places that offer custom cutting – these companies generally end up with scrap cutoffs which are generally too small to be easily sold, but suit the needs of FRC perfectly. The easiest donation to get is something that would’ve been thrown away otherwise.