Re: A small CNC mill for parts, prototypes, electronics. . .
 

Simone

In case you did not know, the FRC build season is 6 weeks long, starting the first Saturday of the calendar year.

What is the expected life of the spindle motor? What type of bearings are used in the spindle motor? Are replacement parts readily and quickly available? Is it possible to run the mill continuously, to churn out multiple parts, for several days at a time or is there some cool down period required between jobs?

Is there some way to hook up a vacuum when milling PCB's? The dust from some PCB materials (fiberglass) is not particularly good for you.

Do you anticipate developing a version with a larger build volume than your current model (5.5" x 4.5" x 1.25")?

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Since I started, I think I've had about 6 made. 3 of one copy in 2006 and 3 of another in 2010 (technically because we could fit 2 boards on the min size panel).

Re: A small CNC mill for parts, prototypes, electronics. . .
 

"The average FRC team" does not have the tools to make PCBs. Your question is similar to trying to gauge the demand for a bridge based on how many people swim across the river.

In the time I've been with the TechnoKats, we have designed and had built several hundred LED panels, a hundred or so small PIC-based controller boards, and about a dozen and a half largish Arduino peripherals. We've also hand-wired a handful of small boards that would have been well suited to in-shop circuit board fabrication.

On the other hand, there is a dedicated PCB router that has been sitting idle and decaying in the shop since before I joined. Nobody still on the team has the slightest idea how to use it, and I'm likely the only one who really knows what it is.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Milling PCB's is a waste of time IMHO, It made sense a couple of years ago when the typical minimum to get a PCB manufactured was 85$ but now you can get beautiful double sided silk screened boards made in a few days for a couple of dollars. The lack of a solder mask on a in shop fabricated board makes smd soldering almost impossible.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Hello!

The spindle motor is a belt-driven, brushless DC motor, and out of roughly 250 machines that we have shipped, we have had one bad motor that needed replacing. I run the machines all day, every day and have yet to need a motor replaced.

The machine is fully enclosed, although you can pause the job and vacuum as necessary. We recommend using FR-1 board instead of FR4 in the machine, to avoid the fiberglass issue.

Even if you don't need it regularly for PCBs, it's there and available if students want to branch out and experiment. It's also great for milling sprockets and other small parts to spec.

It works straight out of the box with our software. No kit to set up or calibrate, and novices can go from set up to miling in about an hour. Our interface for the machine is on OSX, but there is also a relatively user-friendly way to run it on a PC if you are not Mac compatible.

It works on g-code and on the same principles as the big machines, so if a student didn't have access to a full machine shop, the skills they'd learn on an Othermill would give them a head start when and if they did.

Plus it's great for practicing CAD and CAM with.

Sadly, given lead times and holidays, it will not be arriving in time for this build season. But if you are participating in other competitions in the spring such as RoboGames, Botball, or Vex events, having a mill would be a great chance to get your students using it and comfortable once the 2016 FIRST build season starts!

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Learning how to mill plastics or very thin metals on an Othermill would teach students very little about running a Haas in a professional shop IMO. G-code is a very small part of being a machinist. The other parts which the Othermill does not take into account are far more important.

What makes the Othermill worth the $2000 price tag over a Harbor Freight mini-mill CNC mod?

Re: A small CNC mill for parts, prototypes, electronics. . .
 

This seems like a cool tool but I don't see much use for it in the FRC world. It does seem like a nice tool to have to learn CNC and I think it could be a cool teaching tool. I really can't imagine it really doing any milling though, and FRC teams really only would use a CNC machine to mill parts. It seems like more of a engraving tool, which I think it would be good at. I might buy one just to play around with, and maybe use it to teach CNC.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

If you have the space, a Shapoko would be cheaper for stuff like that.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

I can solder SMD on my LPKF milled circuit boards.
Just apply solder mask or be clever with the board design.

Not that this is relevant to FIRST teams, but one advantage to milling PCB is that you can tinker with the trace characteristics. A trick that can be handy with RF work or high speed digital work (neither of which is a typical FIRST issue).

Not to mention I typically work at around 2AM another thing not all that helpful to FIRST teams unless someone takes that machine home. The design of a ProtoMat 92S makes it unlikely someone is going to just pick it up and wander around with it (it is awkwardly shaped and more than 100lbs).

Team 11 has a Haas TM1-P and NextFAB has a Haas VF3SSYT both of which I have taught on.

Even though both machines use CAT40 tool holders with similar pull studs.
Even though both machines have similar controls.

Just the options between the machines can be a source of confusion.

For example: the umbrella horizontal tool changer will load and unload a tool from the same pocket position (so tool 1 is generally in pocket 1), but the side mount tool changer will generally load and unload tools to the closest pocket while storing the tool/pocket relationship. Such that tool 24 might be in pocket 3. If you call tool 24 the machine knows it is in pocket 3 (generally) as things move around. Till someone gets cute and reassigns a pocket incorrectly or fails to set the tool size/weight setting properly.

Then there's the Renishaw probe I just calibrated on the NextFAB VF3SSYT versus the more conventional workpiece and tool length measuring on the TM1-P with out the probe system.

Even tool path generation can have variance from (just to name some): BobCAD, MasterCAM, HSMWorks.

Even a retrofitted manual mill will generally not introduce systems with auto tool changers. For that you need to move into tools like Tormach with the Tormach Tooling System (TTS) and that ups the costs quickly.

Not that a small machine doesn't have value.
I have a MaxNC mill I am cleaning up.
It has closed loop steppers.
It reads G-code and I can export from BobCAD or MasterCAM to it.
It has a spindle assembly with an ER16 collet.

Why did I bother with that MaxNC mill?
It supports a 4th axis.
It has support for limited rigid tapping.
It has support for probing.
It has support for tool length offset touch off.
I can carry the whole machine with a machine vice by myself.
It fits in a crate that I can ship via UPS.
It has a 1/3 HP continuous operation spindle motor and can handle a 1/2 HP spindle motor.
There is a standalone DRO/control improvement for the MaxNC mills.
Used - it cost me less with improvements, repairs, tools and shipping than $2,000.

In comparison:
The spindle motor on the OtherMill looks to be driving an ER11 spindle cartridge (so the maximum tool shank is smaller).
It uses a 1100Kv motor so it's probably rated at 350W-450W continuous so around 1/2HP.
It looks not to have any of the other features listed above from the MaxNC feature set.
The base price for the MaxNC10 is around $1,600 US.
The base price for the OtherMill is around $2,200 US.

For $2,000 on an open loop stepper system I wonder if the money wouldn't be better spent on a larger footprint bridge mill.
Something better able to work on larger plastic or wood pieces or do carvings that might pay off the printer.
I can see recovering the cost of a machine like that, then building into the next level machine progressively.

I doubt making PCB prototypes like this will pay for the machine any time soon.
Even using my LPKF ProtoMats at around $12k each took awhile to recover the cost with professional work ongoing.
Targeting students means that professional PCB work is not really the goal.

Also it seems to me the OtherMill could (but does not) have a 3D printing attachment.
Then at least it would be $2,200 US towards a dual purpose machine.
The question becomes does the OtherMill control have room to control the potential extruder stepper(s).

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Yeah, there's no real reason to make your own PCBs anymore. Board houses have become so cheap and easy to work with. If you want simple, take a look at Oshpark, they charge $5/in^2 for a 2-layer PCB and you get 3 of them for that price. Just upload your Gerbers, they'll do a DRC, you pay, and receive them in a couple weeks. There are other board houses that will do similar things (and possibly donate their services), but I believe the owner of Oshpark is an FRC mentor and will only use US-based board houses (for US orders).

Re: A small CNC mill for parts, prototypes, electronics. . .
 

Oshpark actually got me my stuff in less than a week last time. +1.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

I'll guess it's because you're in California (according to CD) and I'm in Ohio and Oshpark is in Oregon.

Re: A small CNC mill for parts, prototypes, electronics. . .
 

I see the list price as $2,199. For less than $100 more you can get a Taig CNC mill. I love mine.