[sprcpr]

I am new to all of this and admit that I have no idea what I am doing or looking for as far as a small CNC machine is concerned. What I am is a coach of a small high school robotics team. We currently have no machining capabilities at our school. Anything that requires machining has to go to my Father who has a manual machine in his garage, or to the machine shop up the road. I am looking for a small Milling machine, preferable to go the CNC route, that students could use to produce small parts for robotics. Almost all of our parts are cut out of aluminum or plastic and are pretty small. We aren't cutting steel often or anything hard. I currently have $6,000 to spend plus another 3k-4k that I could add from the school. I have looked at the Tormach but the price is a bit high. I don't know that I can squeeze one in with tooling etc for that price. I looked at a Syil but after reading some of the reviews on here I am concerned. The Smithy looks like a possibility, but it seems like a manual machine? I have looked at a few "used" machines on ebay but I have 2 problems. The first is actually finding a machine that is close and decent. The other is the weight and getting it into the robotics room. I have to get it up in an elevator with a 2600# weight limit. and through a 36" door.

Opinions on what to get? What I should be looking for in total cost? etc?

[txcncman]

If you really want these kids to actually learn something useful, go with manual machines. Otherwise, it is acceptable to let them watch someone else machine their designs on CNC. They can do the deburr and clean up work. I have taught machine shop classes off and on since 2004. Beginners work best with hack saws and files. As they learn more about the forces involved in cutting, they can move up to powered manual machines. Once successful on manual machines, then they can have a hand at some CNC work.

Since it is robotics, you might have them retrofit a manual machine to CNC as a long term project over several years.

[sprcpr]

I go back and forth all the time on this. I have thought about a manual machine quite a bit but I'm not sure. I'm not teaching machining so much as prototyping and engineering. Everyone says "start with a manual machine" but why? The world runs on CNC machines now and so I'm just thinking it might be more beneficial for these kids to learn to operate a CNC. I could be totally wrong. If I was teaching these kids to be machinists that would start with manuals and graduate to CNC I can see.

BTW, we are currently at the hack saw and file level of shop. Almost everything we do is by hand. Right now we have a junk Harbor Freight benchtop drill press with a wobbly spindle and a metal band saw along with a full compliment of said files and hack saws.

[txcncman]

I though I explained why. Many machinists can and often do an engineer's job. Very few engineers can do a machinist's job. Many engineer's create poor designs due to the difficulty to manufacture them. With practical experience on the manufacturing side as a machinist before getting that almighty engineering degree, they make better designs.

"The world runs on CNC machines now..." No. It does not. Out of the over 800 machines shops in the Dallas-Fort Worth area, I have been inside about 50 of them. Almost all of the 50 still use manual machines in their day to day operations. Probably you are used to seeing high end aerospace related machine shops. I worked in one of these for 3 years. They had 31 CNC machines (of varying makes, models, and ages) and 16 manual machines.

Until a human has the concept of the forces involved, they do not understand why the 1/4" HSS end mill breaks when pushed through steel 1/2" deep at 40 inches per minute.

But, by all means, "teach" them CNC. Then you can complete their programs for them and then you can do all of the machine set ups and run their parts on your new CNC.

These are just my experiences. Your mileage may vary.

[sprcpr]

txcncman, thank you for your input and I do agree. My father was a machinist and toolmaker by trade. He shared many a story about having to fix the work of engineers. He always said that the best engineers were the ones that had at least some shop experience. He is retired now but has a small shop. I do some work there but distance makes it not an option for the kids to go. What would you buy? In talking with a local machine shop he suggested a used Bridgeport but looking at the size and weight I don't think it would be an option for getting into the robotics room. I've also been told that many of the mill drills aren't worth the metal they are made from.

Do you think the kids would have a hard time setting up the machine and figuring out the programming? I have zero experience with a CNC machine and that is why I'm here looking for advice. I guess I have a grass is always greener view? I am not a machinist, my father is, and there is another that is willing to help. Both have CNC experience. I totally agree that having hands on experience is important. I have thought about and am very concerned that kids with no experience would pile up and destroy a CNC in short order. I still see lots of manual machines around but I see more and more cheap small CNC machines capable of turning out small parts and prototypes. The one machinist that I work with uses his CNC for almost everything. In his words, "It's just easier" and he feels that the future is all CNC. I'm willing to listen to ideas.

I'm also looking and seeing that I might be able to get more "bang for the buck" with a small manual machine. I don't have a huge budget.

[bebob1]

Get a CNC sherline or a taig. Costs a lot less than a tormach and will actually just fit your budget after you buy the necessary tools, factor in material cost, etc. Saves a lot of space too. If you need a larger work space envelope then youd need a bigger mill, depends how big your parts are.

Youd want CNC if you want to make anything more complex than drilling a few holes and squaring up simple workpiece geometries. If you are doing robotic stuff, chances are you will be designing complex shape = CNC it.

Dont worry about the programming part as you will get better overtime, plus you are not a professional machinist hired to reduce cycle times or optimize tool life. If you know nothing about CNC programming it will be a learning experience no matter what so be prepared to break some tools or workpieces. If you are pocketing, try to use less than 70% of the diameter in step over. The depth of cut should be around 10% of the cutter diameter. Choose proper RPM and feed (you can experiment or when you get better look up tables). This is usually a pretty safe bet parameter if you have to wing it

Lots of CAM software are free too. But otherwise youd have to factor CAD and CAM cost.

[awerby]

Like Bebob said, Taigs and Sherlines are perfect for this sort of thing. I'd say get a CNC Taig mill and a manual Sherline lathe. You could get both within your budget and still have money left over for software and tooling. While it's nice to get the feel of things first on a manual machine, it's not essential. Kids these days are pretty comfortable with computers, and there's a lot of software that's not really that difficult to learn. DeskProto, for instance, is pretty simple, and the educational pricing makes it very affordable for schools. Just make the kids wear their safety glasses and keep their fingers away from the machines before they start; these little machines are quite forgiving of beginner's mistakes, unlike bigger and more powerful ones.

Andrew Werby
www.computersculpture.com

[bebob1]

Yeah, and theres also the point that both a CNC taig or sherline are still manual machines. The steppers are dual shaft and allows hand wheels to be mounted. You dont lose manual abilities unlike some other dedicated CNC machines. Its actually best of both worlds, you can do manual when you want. But youd more than likely gonna use CNC anyway. A tormach is a CNC only machine. Pseudo-manual has to be done with the keyboard or electronic jog dial.

[awerby]

While you can move the axes with the radio dials on the ends of the 2027 model Taig mill, that's not really useful for machining, because the calibration dials have been removed to make room for the motor mounts. It's better to do "pseudo-manual" milling using the MDI function. And there are no dials on the DSLS 3000 Taig, since the back shafts are used for the encoders.

Andrew Werby
www.computersculpture.com

[smallblock]

I am new to all of this and admit that I have no idea what I am doing or looking for as far as a small CNC machine is concerned. What I am is a coach of a small high school robotics team. We currently have no machining capabilities at our school. Anything that requires machining has to go to my Father who has a manual machine in his garage, or to the machine shop up the road. I am looking for a small Milling machine, preferable to go the CNC route, that students could use to produce small parts for robotics. Almost all of our parts are cut out of aluminum or plastic and are pretty small. We aren't cutting steel often or anything hard. I currently have $6,000 to spend plus another 3k-4k that I could add from the school. I have looked at the Tormach but the price is a bit high. I don't know that I can squeeze one in with tooling etc for that price. I looked at a Syil but after reading some of the reviews on here I am concerned. The Smithy looks like a possibility, but it seems like a manual machine? I have looked at a few "used" machines on ebay but I have 2 problems. The first is actually finding a machine that is close and decent. The other is the weight and getting it into the robotics room. I have to get it up in an elevator with a 2600# weight limit. and through a 36" door.

Opinions on what to get? What I should be looking for in total cost? etc?

Take a look at the Shopmaster patriot- it fits your budget and your size restrictions and offers you both manual and CNC lathe and mill in 1 package. There was a post somewhere on this forum from another teacher whose students used one in a national competition and won first place.

Cnc Milling Machine, Metal Lathe Mill Drill, 3 In 1 Machine

[bebob1]

his budget of 6k+ maybe 3k is probably most fitting for a sherline or taig CNC mill and lathe plus lots of tools, fixtures and material cost he still needs to cover, instead of spending money on other offerings that bare bones equals his entire budget.

[Fireman11]

I would go in a completely different direction. I would get a manual bridgeport or clone--perhaps used, and then look at Microcarve's machine.

So
http://www.cnczone.com/forums/diy-cn...p_machine.html
microcarve MV3

used bp
Bridgeport 1 HP Step Pulley Milling Machine, Sony DRO, PF, Nice Running Machine | eBay

If you are a 503c--You could also try and see if a dealer would be willing to donate something, or you buy a machine and they donate tooling.

Think outside the box.

[wizard]

I'm not sure here you are nor the state of your school but back in my day we had a fairly well equipped shop class room. In that regard the class room and tools could be justifiably used by different classes. That is you should be considering the development of an industrial arts classroom that just happens to also support your robotics program.

I go back and forth all the time on this. I have thought about a manual machine quite a bit but I'm not sure. I'm not teaching machining so much as prototyping and engineering. Everyone says "start with a manual machine" but why?

There are advantages either way. The big problem for a high school program is that it is highly likely you will have people in the program with zero metal working experience. It was common in the past to give people new to a machining program a German milling machine (a file) to get a feel for working metal. This before they touched a manual machine.

Realistically going manual means buying more. Thus with your budget you could get a decent drill press, a passable lathe, a bench grinder and a milling machine. Speaking of which I can't imagine how you could run a robotics program without a lathe in the shop.

Note that those are just your machines, what ever you budget for machines you will have to have a like number of dollars available for tooling and fixturing. It would be a mistake to blow your budget on the machine itself and not have the vises, clamps and other hardware needed to run the machines. People often underestimate just how much they will end up spending on this support stuffs.

The world runs on CNC machines now and so I'm just thinking it might be more beneficial for these kids to learn to operate a CNC.

This isn't true at all. Your perspective isn't completely wrong though, CNC is very important but it isn't always the right answer.

I could be totally wrong. If I was teaching these kids to be machinists that would start with manuals and graduate to CNC I can see.

It makes no difference, if the kids don't understand what they are working with they will never be able to design properly.

BTW, we are currently at the hack saw and file level of shop. Almost everything we do is by hand.

There is nothing wrong with that! In fact baring a lathe and bandsaw my home shop isn't much more advanced. I certainly want to advance beyond that as one can't do everything at work, but like you I have a budget.

Right now we have a junk Harbor Freight benchtop drill press with a wobbly spindle

The cheap imports are a problem, I'd get rid of the drill press in exchange for a better one. Even if you go to Grizzly you end up having to buy more drill press than you might want to get one with decent mechanical qualities. That being said I've been impressed with the quality of Ryobi's hardware store drill presses. Still in the end you get what you pay for.

and a metal band saw along with a full compliment of said files and hack saws.

Considering the minimal state of your shop I'm going to suggest a few things that you should consider in working out your budget.

1. A metal lathe large enough to handle parts, shafts mostly, that you are likely to machine. The 7x xx Mini lathes are a possibility but I'd strongly suggest going a bit bigger. However I'd stop at much more than $1500 for the base lathe. More would be better here but you budget is too thin.
2. A Baldor bench grinder. Nothing extremely fancy here as it would be primarily used for rough sharpening of HSS tooling.
3. A Bridgeport like milling machine. Most likely an import, but try to keep the base machine under $4000. I'm actually thinking one of the Mini Bridge port like machines would be a good start.
4. A vertical band saw. You mention owning a bandsaw but I'm thinking it is a horizontal cutoff machine. There is nothing wrong with that but a vertical bandsaw opens up working with sheet goods. The problem we will likely run into is budgetary limitations. You would want a fairly capable machine and I'm afraid that that would blow your budget.
5. A one inch belt sander. This for deburring. Kalamazoo makes an ideal solution for this need.
6. Tooling and fixturing. This is something you have to be careful about as you can easily outstrip the value of your machines in purchases here.

Now all of this sounds fine and all but do realize as a school you have options that an individual might not have. At one time the federal government had a program to offer surplus equipment to schools for free. This was well over 30 years ago but that is how my high school acquired more than a few lathes and other tools in its shop. Very good lathes at that. I can't say if the program still exists but I wouldn't be surprised if it is still active, the government regularly disposes of machine tools through auctions to the public. I'm not sure even who you would contact but a congressman ought to be able to help. In reality the expense isn't zero, the machines have to be moved into place, cleaned up and brought up to standard, but you can't save tens of thousands of dollars even if you have to buy the hardware.

This may take you a year or two to get your shop started after which you really should look into some sort of CNC router. This would allow for work on sheet goods and aluminum and would have many other uses at a school. It this case I think it is the best place to start with CNC, considering the goals of the robotics program. A CNC mill isn't something to forget about though, I just think a router like machine would have a quicker payoff and maybe draw enough interest at school to support other classes.

All of this talk of robotics is a bit misleading as what it really is, is a fresh name for an industrial arts program. I think you will have more success with funding if you pass off the quest for tools to support a broader initiative. It is far easier to get adminstration buy in if that CNC router can be leveraged for more than a robotics class. The same goes for basic tools like a lathe.

By the way a real shop class room has to be fairly big to allow safe positioning of the equipment and work areas. Access needs to be controlled.

[wizard]

You should consider yourself lucky. Seriously take some time, and a pot of coffee to sit in his shop and talk to him about the basics. Look around at what is in his shop and try to mentally answer in your mind why each piece of eqipuipment is there and then talk to your father about why it is there. You do this and you might change some perceptions you have about what is needed in a robotics / industrial arts shop.

txcncman, thank you for your input and I do agree. My father was a machinist and toolmaker by trade. He shared many a story about having to fix the work of engineers. He always said that the best engineers were the ones that had at least some shop experience.

Bingo! It is the same for auto mechanics the really good ones where likely taking engines apart before they even attended formal training. The same can be said for electrical engineers or even computer programmers.

He is retired now but has a small shop. I do some work there but distance makes it not an option for the kids to go. What would you buy?

Well talking to your father might be very enlightening. Like I said, how he has set up his shop might shed some light on what is needed to get started.

In talking with a local machine shop he suggested a used Bridgeport but looking at the size and weight I don't think it would be an option for getting into the robotics room.

Good machinery is heavy! This guys reccomendation is a good one if going used isn't a problem. As to your classroom, I know nothing about your school but for a number of reasons you should have a dedicated room for the machine tools. Ideally this room would be on the ground floor with a solidly constructed concrete floor. I'd be surprised if the ground floors in your school couldn't handle a Bridgeport but this should be checked. A far bigger problem in most school rooms is AC power which may be minimal considering the power requirements of machine tools. This doesn't even get into the issue of three phase which is easy to deal with on smaller machines.

A Bridgeport sized machine is actually a good place to start if your budget can stand the expense. My impression is that you are in tough shape as you have a need for far too many things considering your budget.

I've also been told that many of the mill drills aren't worth the metal they are made from.

That depends on how you judge things. If you look at the forums here carefully you will find examples of people doing really nice work with the small mills. The G0704 is one machine taking especially strong interest from CNC converters. Make no mistake though these are cheap machines and do have real limitations. On the other hand many a machinist would look at a Bridgeport as a light duty mill.

So what I'm saying is question where people are coming from when they knock smaller machines. These machines have their place just like watchmaker lathes have their place. That being said the vast majority of the low cost machines on the market do require a considerable amount of rework to get to the point of doing excellent machining.

Do you think the kids would have a hard time setting up the machine and figuring out the programming?

Yes! Remember you grew up with a father that was a machist of some sort, many of the kids in the class will have no such background and may not know a mill from a blueberry. That isn't to knock the kids it is just a realization that you have a bit of "genetic" knowledge that they will have to learn the hardway.

I have zero experience with a CNC machine and that is why I'm here looking for advice. I guess I have a grass is always greener view? I am not a machinist, my father is, and there is another that is willing to help. Both have CNC experience. I totally agree that having hands on experience is important. I have thought about and am very concerned that kids with no experience would pile up and destroy a CNC in short order.

Hey even experienced programmer have been known to do that from time to time. That is the second reason for E-Stops.

I still see lots of manual machines around but I see more and more cheap small CNC machines capable of turning out small parts and prototypes. The one machinist that I work with uses his CNC for almost everything. In his words, "It's just easier" and he feels that the future is all CNC. I'm willing to listen to ideas.

A good machinist with years of experience on a CNC machine will often find using CNC to be far easier. However one does not learn a specific CNC control overnight nor does one learn the art of machining overnight. It is a certiainty that as a beginner many tasks will be easier to complete quickly on a manual machine for the simple reason that you don't have to learn the specifics of the controls. Once a person become conversant in the use of a CNC controller then yes it can be often far easier to use a CNC machine. The problem is your students, as bright as they are, will not instantly learn to use a CNC controller.

I'm also looking and seeing that I might be able to get more "bang for the buck" with a small manual machine. I don't have a huge budget.

Yes that budget is going to be a big problem, especially when you realize that you really need other tools to go along with the Mill. Plus tooling and fixturing which everyone seems to underestimate.

Before buying anything I'd seriously start doing some research. The first place to start with is your local Federal representative. Inquire about machinery for education, grants and the like. Who knows with a well written proposal you might get a grant for a new addition on your shook to support the classroom. That might sound like pie in the sky but do realize this is actually good use for your tax dollars as opposed to some uses that we often hear about. If you don't get a new addition you might get a brand new machine attached to some bill that gets sneaked through the system. Rinse and repeat for your state representative. Oh if this starts to go somewhere don't under do it, buy a quality machine like one of HAAS, router, Mini or office mills. It is far better for the kids to work on a mill that represents what is out in the real world than to mess with something half baked. These things take time of course, but a CNC mill doesn't mean a manual mill is worthless so continue to move forward with buying a decent manual machine.

Expending the public resources leaves you with local considerations. If you have any business in the area asking for or looking for donations is not a bad way to get a program off the ground. Some businesses are reluctant when it comes to machine tools for liability reasons but believe me they throw away a lot of very interesting things that a robotics program could make use of.

[txcncman]

I'm not sure here you are nor the state of your school but back in my day we had a fairly well equipped shop class room. In that regard the class room and tools could be justifiably used by different classes. That is you should be considering the development of an industrial arts classroom that just happens to also support your robotics program.


There are advantages either way. The big problem for a high school program is that it is highly likely you will have people in the program with zero metal working experience. It was common in the past to give people new to a machining program a German milling machine (a file) to get a feel for working metal. This before they touched a manual machine.

Realistically going manual means buying more. Thus with your budget you could get a decent drill press, a passable lathe, a bench grinder and a milling machine. Speaking of which I can't imagine how you could run a robotics program without a lathe in the shop.

Note that those are just your machines, what ever you budget for machines you will have to have a like number of dollars available for tooling and fixturing. It would be a mistake to blow your budget on the machine itself and not have the vises, clamps and other hardware needed to run the machines. People often underestimate just how much they will end up spending on this support stuffs.

This isn't true at all. Your perspective isn't completely wrong though, CNC is very important but it isn't always the right answer.

It makes no difference, if the kids don't understand what they are working with they will never be able to design properly.

There is nothing wrong with that! In fact baring a lathe and bandsaw my home shop isn't much more advanced. I certainly want to advance beyond that as one can't do everything at work, but like you I have a budget.

The cheap imports are a problem, I'd get rid of the drill press in exchange for a better one. Even if you go to Grizzly you end up having to buy more drill press than you might want to get one with decent mechanical qualities. That being said I've been impressed with the quality of Ryobi's hardware store drill presses. Still in the end you get what you pay for.


Considering the minimal state of your shop I'm going to suggest a few things that you should consider in working out your budget.

1. A metal lathe large enough to handle parts, shafts mostly, that you are likely to machine. The 7x xx Mini lathes are a possibility but I'd strongly suggest going a bit bigger. However I'd stop at much more than $1500 for the base lathe. More would be better here but you budget is too thin.
2. A Baldor bench grinder. Nothing extremely fancy here as it would be primarily used for rough sharpening of HSS tooling.
3. A Bridgeport like milling machine. Most likely an import, but try to keep the base machine under $4000. I'm actually thinking one of the Mini Bridge port like machines would be a good start.
4. A vertical band saw. You mention owning a bandsaw but I'm thinking it is a horizontal cutoff machine. There is nothing wrong with that but a vertical bandsaw opens up working with sheet goods. The problem we will likely run into is budgetary limitations. You would want a fairly capable machine and I'm afraid that that would blow your budget.
5. A one inch belt sander. This for deburring. Kalamazoo makes an ideal solution for this need.
6. Tooling and fixturing. This is something you have to be careful about as you can easily outstrip the value of your machines in purchases here.

Now all of this sounds fine and all but do realize as a school you have options that an individual might not have. At one time the federal government had a program to offer surplus equipment to schools for free. This was well over 30 years ago but that is how my high school acquired more than a few lathes and other tools in its shop. Very good lathes at that. I can't say if the program still exists but I wouldn't be surprised if it is still active, the government regularly disposes of machine tools through auctions to the public. I'm not sure even who you would contact but a congressman ought to be able to help. In reality the expense isn't zero, the machines have to be moved into place, cleaned up and brought up to standard, but you can't save tens of thousands of dollars even if you have to buy the hardware.

This may take you a year or two to get your shop started after which you really should look into some sort of CNC router. This would allow for work on sheet goods and aluminum and would have many other uses at a school. It this case I think it is the best place to start with CNC, considering the goals of the robotics program. A CNC mill isn't something to forget about though, I just think a router like machine would have a quicker payoff and maybe draw enough interest at school to support other classes.

All of this talk of robotics is a bit misleading as what it really is, is a fresh name for an industrial arts program. I think you will have more success with funding if you pass off the quest for tools to support a broader initiative. It is far easier to get adminstration buy in if that CNC router can be leveraged for more than a robotics class. The same goes for basic tools like a lathe.

By the way a real shop class room has to be fairly big to allow safe positioning of the equipment and work areas. Access needs to be controlled.

+1

Step back a little and become the directing manager of your robotics program and get a machinist to step in and teach the actual machining if you are not up to it.

[bebob1]

Also, what has yet to be mentioned is you may need to do welding work too if you are assembling pieces into a bigger part like with sheet metal work.

Im sure he is flexible and open to ideas but I dont know if all this tangent discussion is particularly helpful to the OP. He is asking advice for specific details on known commercial CNC machines that may suit his needs and budget, not to discuss philosophy on how to properly run an educational program on machining. He himself as someone who admittedly has no machining experience, has already stated he is more interested in the end goals than to preach to his class about the practice of machining or manufacturing. Again, hes not trying to teach a machine shop class. His number 1 priority is making the robots, and maybe if the students are lucky get to rub elbows in the CNC field. His motivation for having manufacturing capabilities in house could be many, but it probably involves giving him flexibility and saving him money in the long term since machine shops routinely charge through the roof. He is probably trying to get tools enough to make robots that can enter a First Robotics competition or something like that.

Manual machines are likely not going to be very useful to him depending on what he intends to make unless they are all simple geometries with a few holes drilled here or there. Can you imagine the skills involved in manually machining even simple things like engraved letters? Now try protruding letters. What about machining a matching positive and negative mold for casting a smooth ergonomically designed computer mouse casing with 2 mm thick walls? Even so called 'seasoned machinists' cant do this. Some will say its not normally possible for inexperienced machinist to succeed at CNC? What about manual machining being quite a manual skill in and of itself that maybe they cant master also because of dexterity and hand eye coordination etc? Like sports and art, its not for everyone either. Infact its more likely someone can succeed at CNC machining than manual since youre crunching numbers and doing all the interactions on a computer rather than physically manually turning knobs with your hands which require dexterity. Its like how many more of us can be good at basketball dunking in NBA Live 2013 than we can physically doing it.

Doing things manually or having fundamental understanding isnt always required or even good for an application. Electrical engineers are not taught the fundamental physics but are merely taught the behavior of various phenomenon that are a complex interaction based on the fundamental physics. Yet they do well as that is all they need to make things work that range from designing successful power electronics to microprocessors. Yet most of those that work at AMD designing microprocessors likely dont know a thing about bosons. Or mechanical engineers designing heavy vehicles taking into consideration of mass knows nothing about the Higgs Field. Sure we should teach people how to manually calculate math before giving them calculators, but nowadays we teach them enough of the basics and give them the calculator because times have changed. We dont fail someone because they cant do exeeding long and complex math or be able to do them fast; we simply say they should use a calculator. Sometimes computer control is also mandatory. Some supersonic aircraft are aerodynamically unstable and require constant autonomous controls over a variety of actuators to fly. The amount of things needing human interaction will overwhelm any human operator, so the only way they can work it is with computer control.

There are CAM software out there that pretty much takes most of the required understanding of G-code programming out of the user also. Like Deskproto. As long as you have any sense of material fixturing and know what processing steps to use to clean off a part, then you just load the file in, put some settings and press go. No need for fancy stuff like programming trochoidal tool paths to attack corners to minimize chip load and make better corners. Not until your application tolerances demand it or your tool life isnt holding up to expectations. The dentistry field has been doing something similar for ages in machining dental crowns. Its all plug and play. Scan patient data, replace standard workpiece, press start, wait, and out comes final product. Dentists didnt care about learning G-code programming.

And plus, with all the talk about needing to bring manufacturing back to north america, CNC is the better general direction to approach for educating future generations because it is the only way you can find an edge over the international market in this climate. There will always be other countries that can pay their workers cheaper, lower raw materials, etc compared to the costs of doing it here. The only way to get an edge is to make it faster and better here and CNC and automation is the only way.

The analogy is where an old generation probably disliked phones, know or heard nothing about the internet, and think you should write letters as they continue to do so. The next generation comes along, uses phones and fax machines but doesnt use emails. The next generation uses MSN messenger and emails and now onto Twitter while not using fax machines or write letters. Changing times demand changing skills and changing our devotion to certain aspects of doing things in place of other more effective methods.

[allesg]

The core of this discussion is about starting out with manual experience or just plunging in with CNC programming.

I started out in my CNC learning experience thinking it was just an extension of my already broad background in Hardware, Software and CAD. I was wrong.

It wasn't until AFTER I had experienced creating parts by hand on mills and lathes that I finally appreciated the fact that CNC machining is not just programming, software and selection of cutting depths and speeds from charts or formulas. It is not just a science that any high school kid with a nintendo or gameboy and some windows experience can just pick up. (you should also know trigonometry) CNC machining is more than a SCIENCE - it is also an ART. That is where hands on machining experience becomes required.

Taigs and Sherlines are very versatile and they can be converted to CNC, but I second Fireman11's suggestion about Microcarve's CNC machine. They are VERY inexpensive and much more capable than they appear. They are perfectly capable of making quality parts.

John, the guy who designed the machines at Microcarve.com and elsewhere, is an exceptionally talented engineer that has worked a minor miracle thru trial and error with what might appear to be a collection of junk parts. The magic is in the PRECISION DETAILS of the metal parts and the tensioned structure. John is an engineer's engineer.

Spend the time it takes to read thru his CNCzone threads and you will realize that you could have your students assemble their own CNC machines with inexpensive parts.

Buy, assemble and use one of his kits yourself and the mystery of the electronics and mechanics of the machine with vanish. Once asembled, getting one to run is the same as with any of the other Mach3 machines discussed on CNCzone.

To summarize, a great curriculum would include manual machining, trig, cnc
programming in G code and possibly the asembly of a simple CNC machine.
CAD and CAM can follow once students machine some simple parts out of
wood, delrin or aluminum.

[bebob1]

I dont know if you have special interests or you are a proud owner, but you are being a little misleading about the microcarve.

Between the microcarve, sherline and taig what is the difference? From a wide angle perspective, essentially all three are 3 axis vertical milling machines. Except that in terms of machine stiffness it goes in this order: Taig, Sherline and microcarve.

The microcarve kit also costs around $650 before tax and delivery. This is just a barebones with no spindle and no steppers or drivers. Assuming you can find a way to make the bracket to hold your spindle (which youd have to figure out before having a functional mill), that spindle probably costs $300 at least. Some people put wood routers that are on the order of that price and more. Plus, wood routers are high speed spindles. Sometimes its better to machine with lower speeds, in this case you'd want a sherline or taig style spindle. A taig or sherline style spindle offered by those manufactuerers come at around ~$600 dollars purchased on its own. So if you are going this route thats on top of the $650 for the barebones microcarve frame.

Lets not forget that spindles like those offered by sherline or taig can be used to adapt a wide variety of tools, such as fly cutters, boring heads etc. If you simply tack on a wood router onto the microcarve, you cant use those capabilities.

So all in all, CNC ready bareboones for sherline and taig costs around $1k. The microcarve is likely to be $1k or more. Essentially they are all in the same price range when it comes down to it. So in what way is it better again?

[sprcpr]

First, this has been a great discussion. I appreciate all of the suggestions and that all of you spent so much time responding is really great. To answer some of the questions.
I run an after school robotics program.

Our "shop" is on the second floor.

We are involved in the FIRST robotics program as well as the BEST robotics program.
We have access to the Woodworking shop at the school and that is a big help. But we don't have any type of metal shop. The school sold off a very nice BRidgeport and lathe about 15 years ago despite the requests to keep them by Many of us, most robotics programs are all about industrial arts. The idea is that you add that layer of motor control and feedback. It really is a great program.

It is an after school school program and so we don't have the same kind of curriculum support one would have in a during school activity. I have collected, begged, and cajoled the money I have by thinking outside the box believe me. I have looked on the gov sites for a mill for years. So far nothing unless you want to ship it from Utah to PA. And even then it isn't free. And yes I plan to hit up everyone for tooling and other materials once I know what I need.

I have had this conversation with my dad numerous times. He has an old manual machine (Van Norman #12)and I know how long it takes us to set up anything on that. I also understand that tooling will be a problem but again I'm hoping I can get much of that donated. He has a nice lathe and we have used it quite a bit but he is 2 hours away. We seem to have a critical need for a lathe once a season. We seem to need a mill every other day.

Keep the suggestions coming. I've learned quite a bit.

Found a "PM-45M" milling machine that is new and close. I also like the shop smith in that it comes with quite a pile of extras. Thoughts? BTW I plan on calling several vendors tomorrow.

[jm82792]

I'm 19 and bought a Microcarve for wood working about 8 months ago; and have some input in regards to the software side of things. If your prospective students are at the point where they want to make parts, with the concept of what they want already preconceived I don't see an issue with them using CAD and CAM software.

I'd first get/introduce them into CAD, find some package that's straightforward and is intuitive(I've never used a CAD package, I have used various 3d modeling programs though), avoid the cold shell that some packages have; although they may be extremely capable you don't want hours spend understanding the GUI.

Now, the interesting part where they want to make what they have designed. They have to get the grasp of feedrates and such. I've only cut wood, Ipe isn't aluminum(it's aluminum of wood though ) but I've wreaked countless bits and have made numerous(many laughable, few were complex) errors.
I'm almost tempted to say some students should be groomed(Ei they are very interested and dedicated, especially for the CAM and controller side of things) for using CAM and CAD packages.
Many may love designing parts but may not wish to think about the actual CNC machine and it milling parts.
While others, like myself can't design much of anything yet enjoy continually tinkering with things to achieve faster mill times and better finish quality.

That's just my idea of what you could potentially do, although, I could be totally off base to what your aiming to do