Advanced tools in the workshop (Mill, Lathe, Welder etc.)

[Leav]

Hi,

This year my team used a small cnc mill designed to mill plastic in order to fabricate certain parts (mostly motor brackets) from aluminum.

More complicated or just larger parts were not possible to do in house and were done by mentors or sponsors at other locations.

For next season, I'm looking to push the capabilities of the team forward in two ways: making the team more reliant on CAD (since we had alot of problems with integration which would have been solved by using CAD) and adding advanced fabrication capabilities to the workshop.

I'm trying to learn from the experiance of teams which already have these tools in the workshop, or teams which have tried to integrate them but were unsuccessful for some reason.

some examples:
Mill (either DRO or CNC) - we have shown this season that a bigger, more powerful, mill could be utilized by our team since we have outgrown the capabilities of our small mill.

Lathe - again our small lathe (the size of a pc keyboard) is stressed way beyond it's capabilties and a bigger one could be of great value.

Aluminmum welder - like many FIRST teams, we do alot of aluminum welding and I have been seeing that there are at least a few teams where the welds are done on site by students. I think this is great and awesome and was just wondering if this is practical for any team or are there special circumstances where this is possible/practical.

I'd like input regarding:
1) cost (purchasing, repairs, materials, upkeep...) [let's go for US cost and i'll add 100% to every number..]
2) difficulty for students to learn (how long would the training take, for example)
3) safety (can the students use the machine at all? can they do so unsupervised?)
4) anything else you have to say on the matter!


Thanks for your input!

-Leav

[EricH]

For a mill and lathe, you could probably train the basics of both of them in a couple of weeks. More advanced stuff would take longer, of course.

In terms of safety, as long as proper precautions are taken (safety glasses, etc.), you could probably, depending on site insurance of course, allow students to use the machines under supervision. Supervision doesn't have to be leaning-over-your-shoulder; it could easily be, "I'm going to be in this area keeping an eye on you; you never know when I'll show up right next to you."

CNC mills and lathes are probably a little bit too much at this point; I'd go for a manual that can be converted over later, if needed.

[MrForbes]

In the US, there used to be vocational training at most high schools, but that is mostly gone now. Community colleges have taken over most vocational training, and there are some programs where high school students can take classes at a community college. In an ironic twist of fate, it seems that these days the "math and science" students need to take the vocational classes so they can learn the fabrication skills necessary to build robots, and then go to engineering school.

Learning to TIG weld aluminum takes time, and some people are better at it than others. I am not very good at it, although I took some community college courses. I have seen some great welding work by high school students, but students with both the skill and the motivation to become good welders are rare.

You might want to consider using CAD to help you design the robot, but design it in a way that you can build the parts using the existing manual equipment you have, or so that it can be built with less expensive manual equipment you can buy.

We did this successfully last year, making a CAD model of the robot that we built out of wood, pipe, simple aluminum pieces, etc. The trick is to consider how you will fabricate the parts as you are designing them, and keep improving the design to make the fabrication process as simple and easy as you can.

[Andrew Bates]

Can't help you with cost but as for teaching students how to run a mill or lathe our is something team has been relatively successful at. It usually involves several meetings of standing with them and showing them exactly what to do and explaining the process of making a part step by step. In the end we have several students who we know we can let run a mill or lathe by themselves. Others we know that we can be one machine over and they would still be fine. It usually takes about one build season to get a student to the point where they are really comfortable on the machine.

As for safety, it always comes down to not being stupid. Out of a mill and a lathe I would say that the lathe is the machine where students are more likely to get hurt, if they have long hair or wear a tie it could get caught by the spindle and suck them in. However in the end it comes down to teaching the students right way to machine and they should stay safe.

[Dick Linn]

I don't know if you can get used equipment. As far as new low-end Chinese lathes and mills, you might look over the items and prices here:

http://www.grizzly.com/products/cate...spx?key=460000

http://www.grizzly.com/products/cate...spx?key=480000

DROs and mill tooling aren't cheap.

Either one can be dangerous. Here's something I came across about a year ago:

"There was a "very serious" accident at the local high school last week. I use the quotes because I have not heard clear details yet. In fact, my account may not be accurate, but I don't think it matters for the purpose of this discussion. One member of the school robotics team (15 total) was running the lathe, and while bending over to look at her work, her hair tie snapped and her hair got caught, pulling her right in.

Update: The girl was released from Stanford Saturday afternoon and is now being considered for a unique operation to try to save the ends of 3 fingers which were caught in the windings of her hair as it was wrapping around the auto feed screw."

The cost for a setup to weld Aluminum will vary with the process (MIG or TIG) and what thicknesses you need to weld. A 175 - 200 Amp MIG welder would be the minimum I'd recommend for around 1/8". A spool gun is an option to consider, as a regular MIG gun doesn't feed the soft wire very well. Here, a minimal MIG setup is perhaps $1,000-$1,200 with a tank of Argon. The least expensive unit with a spoolgun: http://www.northerntool.com/shop/too...2663_200392663

TIG is considerably more expensive. About the least expensive unit I'd consider is this one: http://www.millerwelds.com/products/tig/diversion_165/ Add gas, Tungstens, filler and safety gear and you're talking $2,000. Safety issues include fire/arc protection and handling/storing high pressure Argon.

[Leav]

Originally Posted by squirrel

You might want to consider using CAD to help you design the robot, but design it in a way that you can build the parts using the existing manual equipment you have, or so that it can be built with less expensive manual equipment you can buy.

This is good advice. throwing more money/technology at the problem isn't always the best solution.

I think i'll still try to get at least some form of mill and lathe, since you can't really get away without these capabilities I think... (if you want to do stuff mainly in house, that is).

But you are definitly right in the respect that we don't need any more than 3 axes on the mill and 2 on the lathe (just the most basic setup).

I'll give TIG a try myself.. I have to know how to do it in order to teach the kids so that's the first barrier to pass and will also give me an indication of how difficult it is for the kids to do.

Still looking to hear from teams who have these stuff regarding how they use them.

-Leav

Edit:

Originally Posted by Dick Linn

Either one can be dangerous. Here's something I came across about a year ago:

"There was a "very serious" accident at the local high school last week. I use the quotes because I have not heard clear details yet. In fact, my account may not be accurate, but I don't think it matters for the purpose of this discussion. One member of the school robotics team (15 total) was running the lathe, and while bending over to look at her work, her hair tie snapped and her hair got caught, pulling her right in.

Update: The girl was released from Stanford Saturday afternoon and is now being considered for a unique operation to try to save the ends of 3 fingers which were caught in the windings of her hair as it was wrapping around the auto feed screw."

I'll admit this shook me up... this is not something to brush off.
is there a further update regarding the status of the girl?

[Dick Linn]

I never heard any more about the lathe incident. It was part of the safety discussion here:

http://www.chiefdelphi.com/forums/sh...ad.php?t=65978

TIG requires a good deal of dexterity and coordination but is a skill worth learning.

[Joe Lambie]

Good call on going with the mill and lathe. I would estimate 90 percent of the parts a team would make can be made on a decent mill and lathe. If you are crunched on space on option is a mill/lathe combination device. There are pluses (one machine needed to complete many different tasks) and minuses ( only one type of machining operation can take place). One of the most important is making sure the machine is calibrated properly, both the manual dials on the axis hand controls and the digital readout. On Team 93 we have our own machine shop (it is the High School shop) which has several mills and lathes at our disposal. The biggest issues is maintaining them and losing calibration as these will see higher levels of abuse than normal; students learning new skills often make mistakes that result in damage or extra wear and tear. This is something to keep in mind when buying the equipment.

As for how we use them, our goal is for students to be making the majority of parts. When I was a student on the team I learned a lot and now as a mentor know these students gain a lot of skills by being in the shop making the parts they design. It gives you a sense of what can and can't be done. The machines are used to make everything from frame members in which we use the mills to precisely locate holes, to complex hubs and device parts. Also, the machine tools can be used to make some complex parts, with the right tooling. Be sure to have a good vice for your mill, along with dial indicator to check squareness. Also, a good 3 jaw self centering chuck can accomplish most things on a lathe. A typical process for us is to use a lathe to turn a drive shaft of some sort, then go to the mill, and cut a keyway in it. Most operations like that are done by students with mentors nearby.

As for the welding, its handy to be capable of it but I have had seasons in which we have built robots without any welding at all.

One thing to seriously consider when moving up in size/quantity of machine tools is trying to have access to experienced machinists and tradesmen. Often they have seen things go right and wrong and are invaluable resources to have working with students (and mentors). It is amazing what can be done on a manual mill with a quality Digital Readout Device and some knowledge about setting up the machines.

Sad to hear about the young lady, a harsh reminder that these tools are neat to use they need to be respected. I have been involved in my fair share of close calls, and always am sure to teach students the importance of respecting the tools we work with.

If you have any questions or want some additional information let me know! If I don't have the answer, I promise I know someone who does in the arena

[sanddrag]

We have a small round column Jet mill at our high school, and while it's certainly useful to have, it's not our go-to place to make something. I'd say we use it only about 10 times over a season (mostly for reworking), as most of our parts are made by sponsors, with larger, more advanced CNC equipment. Probably fewer than 10% of the parts we design/make are practical to do on a manual mill.

Having a lathe is very useful. I'd recommend a lathe as one of the first purchases. I've had this lathe at home for 4 years, and although it's small, I'd say it can do about 90% of the parts a typical FRC team would need. If your budget allows it, they say to buy the biggest machine you can afford.

For milling, there's a few teams who have the Tormach CNC mill, which seems to be a good value and size for an FRC team. To be serious about making anything by CNC, I would not consider a machine smaller than this. A lot of the parts on our robot could probably be made on a machine like this, but definitely not a machine smaller than this.

Even if you have a CNC mill, a manual mill can still be useful for one-off parts and simple parts. Not sure how the used machinery market is over there, but if you can find a Bridgeport, (or similar knee mill) that would be a good choice. I've also heard good things about the Industrial Hobbies mill.

For tooling, plan on spending up to half of whatever your machines cost, just for tooling. Vises, chucks, collets, end mills, blades, drill bits, boring bars, tool holders, etc really add up fast.

Do you have a good way to cut bar stock and plate? I think some good saws are essential. I would recommend at the least, a 14" band saw. And if you can get a horizontal band saw, and/or cold saw, and miter saw too, even better.

Do you have a good sturdy drill press? What about an arbor press and a set of broaches? I'd say an arbor press is a must-have item. And howabout a belt/disc sander too.

Having a TIG welder at school would be most useful. This year we spent a full week straight, of 7-hour days at a sponsor shop welding. And then another two 3-hour days at another sponsor shop.

[Joe Lambie]

Originally Posted by sanddrag

Do you have a good way to cut bar stock and plate? I think some good saws are essential. I would recommend at the least, a 14" band saw. And if you can get a horizontal band saw, and/or cold saw, and miter saw too, even better.

Do you have a good sturdy drill press? What about an arbor press and a set of broaches? I'd say an arbor press is a must-have item. And howabout a belt/disc sander too.

I second those thoughts as well. Didn't think about the importance of the basic tools to make the advanced tools more useful.

[Siri]

We only use a MIG welder and a large lathe on-site. (We also have a large manual mill, but logistics have kept us from using it.)

1) Cost
- Lathe: I'm pretty sure our lathe is older than I am and was probably a donation at some point, so unfortunately I can't help you there. We don't use it much, so upkeep isn't a big problem, but overall it's pretty robust. We haven't had to do anything for it in at least 5 years.
- Welder: Our Clarke Hot Shot Spool Gun MIG welder ran us around $300-$400 (US). Replacement spools are generally under $10, and depending on the contact tips get, you can get 10 for $15. Spools last us a while--maybe one per a build and a post- or pre-season. We go through tips pretty quickly though, especially if we're teaching new people (or don't know to replace the liner), maybe 1.5 packs per build season or so. The liner has to be replaced every once in a while (we just did our first after 1.5 years), but it's also less than $10. You can get argon refills for like $30, which you'll have to do ever several months depending on how much you use it. Our 2 auto-darken helmets ran around $50 each. Welding-grade gloves, if you don't have them, will probably run around $10 per pair. We went to Good Will and got a couple cotton button-downs for very cheap as well. You'll also want an angle grinder, which I think ran us not a whole lot under $100. I can add up some, but for us it's been a wonderful investment.

2) Difficulty for Students to Learn
- Lathe: Depends on who's teaching. We went several years without a mentor who really knew how to use it, so figuring that out safely understandably took a while. It's not particularly difficult to learn once your teacher really knows it, though.
- Welder: I was my team's first student welder (or any welder, at that). We had a few people floating around who knew something about it, but for the most part I had to figure it out for myself. I spent a good chunk of the pre-season practicing, but by build I cranked out the chassis pretty fast. It's certainly not an impossible skill to learn, but getting good (as with many skills) takes patience.

3) Safety
- Lathe: Sure, students can use it if they know and follow the safety precautions. We don't currently have a student that's proficient enough to do so without direct supervision, but we probably wouldn't let them anyway.
- Welder: Students can use it. On our team, no one uses it unsupervised.
In general, we don't want any team member using power tools without someone else present (though not necessarily in an over-the-shoulder role, just nearby).

4) There's certainly something to be said for teaching students advanced machining skills--I thoroughly enjoyed welding as a student. You can, however, certainly do without them. Many (albeit perhaps not most) teams fabricate winning robots without any at all. We spent our first four years without any significant welding, milling, or lathing, and even now limit the latter two to not more than a couple components per year. In fact, we won a regional Innovation in Control award last year without either.

Personally, I consider the essentials to be more a good drill press, vertical band saw or the like, and a belt sander, maybe a horizontal band, jig, and dremel. More importantly though, the most essential thing is being able to design for your capabilities. What those entail are at you and your wallet's discretion, but in the end bricolage is an important skill to have (just ask the Apollo 13 guys). That's what we aim to teach our students in terms of design and CAD, which at least to me is much more important than advanced machining. Yes, the sky's the limit, but I'm not buying you an Ares V--figure out how to get there.

[Tom Line]

I've had to correct students numerous times about the dangers of tools. The most common issues I see:

1. Girls (more rarely boys) with long hair that is not restrained. Or jewlery. There's a reason most shop folks don't wear it.

2. People using gloves. Good Lord, but I hope FIRST stops pushing gloves. They are a HORRIBLE idea around any tool that spins - dremel, drill, drill press, lathe, etc.

3. The usual safety glasses

4. People trying to hold on to parts on the drill press rather than using a vice

5. People using the bench grinder incorrectly (resting parts on the backstop and placing their fingers in the way of the pinch).

It's seriously enough to make me fight any inclusion of a serious machine-shop style tool in with the general build group. They need to be seperate and apart. They don't go along well with horseplay, and a small bump in a crowded space can spell disaster.

Right now we do pretty well with a drill press, grinder, vise, arbor press, drill, and saws-all in our build facility. Our mill facilities are at a mentor's house where we can tightly supervise who goes there (just a couple at once) and how it is used. Having big machine tools within reach of 30 kids is a disaster waiting to happen. The mill is new (to us) this year and has been a wonderful addition. We got it for $500US because it had a burnt out motor and then one of our more industrious mentors replaced the motor and did rehab work on it.

[eugenebrooks]

TIG welding is practical on site, we do our TIG welding in the
school shop. It is essential to have a experienced TIG welding
mentor available, but TIG welding of aluminum can be picked
up by students with close guidance from a mentor. The smallest
welder would be a 250 amp unit, the smaller 175 amp units
are stretched a little too much for some situations involving 1/8
aluminum and can't deal with anything thicker.

[Doug G]

We do almost 100% of the robot in house. Assuming you already have a cordless drill and a drill press; here's how I'd rank our advanced tools...

1. Metal Chop Saw is probably our most used tool.
http://www.amazon.com/Porter-Cable-1.../dp/B0000222X3

2. Disc / Belt Sander is a must as well, and get extra sanding discs and belts.
http://www.amazon.com/708598K-JSG-6C.../dp/B00005NMRO

3. Tig Welder would be next, as others have said, 150 Amps minimum
http://www.denlorstools.com/home/dt1...hob500425.html

Accessories would be 2 Argon tanks (one always runs out on the most important day!), 2-3 helmets, gloves, electrodes, extra ceramic torch ends, filler and a nice flat metal table.

4. Vertical Band Saw, 14" is good. Get extra blades. Local hardware stores usually only carry blades for cutting wood. So be sure to get blades that are 1/4" or so wide and have 12-18 Teeth per inch.
http://www.rockler.com/product.cfm?page=21646

4. Manual Mill... The 3-1's are iffy and would not recommend them. As others have stated, half the money goes to the machine, the other half to the tooling. DRO is so helpful. Our has a DRO retrofit which works just fine.

5. CNC Benchtop Mill... We use a CNC Jr. from CNC masters, and there are others as well for ~$10-$20,000. Don't retrofit your one and only manual mill. Once you have a manual mill and all the tooling, you don't have to go get more tooling for the CNC mill. BUT you should figure in the cost of software. We use MasterCAM which is AMAZING.

6. Arbor Press and a set of broaches (keyway and hex).
http://www.dumont.com/prod2c.html
http://www.google.com/products/catal...wAA#ps-sellers

7. Lathe... We have a small benchtop lathe to turn down shafts and such. Unfortunately it doesn't allow us to deal with things larger than an inch. We rarely use the lathe.

[Creator Mat]

for some of the better funded teams out there the plasma cam could be something to expand your workshop. It costs about $9,000 for a low end model to $25,000 for the high end models. Sadly my team does not own one, so i can't give a personal review but it seems like it could be something pretty handy for a robotics team.