[utamaverick2004]

Hi,

I'm a newbie, been doing some CAD designs, now it's time to see if I can output any of these as real objects, models and other prototypes.

I've looked a several designs, kits, pre-builts and the prices run the range from a little to a lot. Some even involve sourcing parts from China. So that might mean customs costs.

The Momus has what I'm looking for and a decent set of plans to get started, but the question remains - "How much can I expect to spend on building a working unit, all parts, software and router?" I've already got a PC set aside to dedicate to the CNC machine.

Are there any potential problems with parts sources in the plans?

Which parts are the most difficult to obtain for the project?

Which parts are going to be the most costly to acquire?

I'm starting with a radial arm saw, a circular saw and hand drill.

Already have a sheet and 1/2 sheet of OAK veneer plywood left over from some bookcases I made awhile back for the enclosure. But everthing else is going to need to be purchased.

Also have a student license for AutoCad Design Suite 2013 that I'm still learning to use. I have been mostly a CorelDraw user for many years and an on/off user of IMSI 2D/3D cad.

I'm taking classes now and will hope to use this CNC machine to show off some of my designs next semester (assuming it's all up and running and I can afford all the parts by then).

I know I'm a long way off from completion of the unit. This is all new for me, but I know better to "cut once and mearsure twice" so I'm asking for insights before I start.

[GTFreeFlyer]

I'm putting more into mine than needed, including a built-in PC, and I'm running about $2400. In addition to that I spent 400-500 bucks on tools for my garage, used to build the machine. More than half of the 2400 is electronics. That's your most pricey stuff. Everything else is cheap an easy to get a hold of. There are just so many pieces that $3 here and there plus $5 shipping here and there starts to add up really quickly. I got almost everything I needed online an it was fun for a few weeks having a new package at my doorstep everyday I came home.

I'd bet that most of the prices range widely from $1200 to $3000, but that's just me pulling numbers out of the air. It all depends on what you already have and what you want to put into it.

[OCNC]

Are there any potential problems with parts sources in the plans?

For anyone living in the US the parts should all be readily available.

Which parts are the most difficult to obtain for the project?

I found it difficult to locate cold rolled steel that was straight so I substituted ground flat stock. It cost a little bit more but was vastly superior to what I was finding for cold rolled steel (your experience may be different). I also increased the footprint of the machine to accommodate the standard 3' lengths that are available in ground flat stock.

Which parts are going to be the most costly to acquire?

Actually all of the parts separately are not that expensive so it ends up being the total accumulation of parts that constitutes the cost of the machine. You can of course spend more than the bare minimum for the electronics which will tip the scales towards that end should you be so inclined.

I'm starting with a radial arm saw, a circular saw and hand drill.

I would say that the one additional tool you should have or have access to is a small drill press. You will find it very difficult at worst and quite tedious at best if you have to drill accurate holes in aluminum bar with a hand drill. You also need some basic layout tools (scriber, small machinist square, layout blue, center punch, spotting drill) and a few drill bits and taps (along with a tap wrench).


The basic mechanical aspect of the machine is quite simple to build as long as you can easily drill and tap holes. I had no need to build an enclosure. My base is shown in a rendering below. The white material is 3/4" two sided melamine particle board. The yellow frames are made of scraps of 3/4" cabinet grade plywood that I had laying around. The green side panels are 1/2" birch plywood scraps. The frames were built on a simple jig that kept them square and dimensionally identical. The lap joints were glued and stapled with 1/4" crown staples but screws could have been used instead. Once the frames were made the unit was assembled first with nails (pneumatic pinner) and then with screws. I assembled the unit on top of my table saw to maintain flatness. It only took a couple of hours to build the base not including the time for glue to dry. The mechanical components were then attached to the top of the walls. It assembled very quickly. One thing not mentioned yet is the need to collect dust. Dust collection ends up being an overlooked aspect in the rush to get the machine up and running but once it's running you will quickly realize how important it is. Consider then that you will need something in your budget to deal with this eventually.

The last thing I think of that hasn't been mentioned is that you need controller software. Typically Mach3 or LinuxCNC (EMC2) are what you see being used most often in the DIY world.

Chris

[GTFreeFlyer]

Good call, OCNC, on the drill press. I'd say this was the tool that was used the most as it accounted for nearly 95% of the metal fabrication, and also used it a bunch on the wood too. I picked up a cheap one at Home Depot for around $110 or so and it worked great. Next one I'll buy will be much more precise and rigid though.

Number two most used tool is a tie between the router and the circular saw for the wood fabrication.

I encourage you to use the router as much as you can before mounting it to the CNC machine. I learned a bunch just by pushing it thru the wood by hand. You really get an idea for what it is capable of and this will help you make better estimates for feeds and speeds later on.

[Friction_Burn]

momus cost by Friction_Burn, on Flickr
This is what I have spent on my machine so far. I still need to get the materials for the base. Ive had most of the tools already and I'm able to use a drill press at work during lunches and breaks.
I've probably spent about $50 on tools specifically for building this.

[momus_cnc]

Great spreadsheet. I typically tell people that the bare machine (without motors, electronics, router, computer or software) can be built for around $500 +/- and this seems to bear that out. I've heard of total reported budgets that ran from as low as $800 to well over $3000 (the latter included some software and tool purchases.) I'd say a safe total budget is in the $1100-$1500 range.

Geographical area can play a big factor in shipping costs, especially if outside the US. If you don't need to run a cover that will save some money on plywood and plastic. The plans call for pouring a thin layer of epoxy in the bed area to create a flat reference plane for alignment, but the majority of builders seem to eliminate this, saving $20-50 on resin.

So the big factors are electronics and software. Electronics can run anywhere from $200 for Chinese kits, to over $1000 when including a PID spindle controller, or buying an additional PC. A popular electronics choice is the Geckodrive G540, and complete kits can be purchased for around $500. These are a perfect match for the machine.

Software may be the biggest factor. It can range from free (SketchUp > FreeMill or Phlatscript > EMC2) to tens of thousands of dollars (Solidworks or Inventor > MasterCam > Mach3). Software choice may be driven in part by the complexity of the parts you want to make. More complex part geometry requires design software that can model it, and CAM software that can generate appropriate toolpath strategies. The plans have a list of software suppliers in the back, and I'd highly recommend downloading trial versions and seeing which ones might work for your needs. Many people find the software end of things to be the most daunting, so it is a wise idea to try and figure out that workflow a little bit, before jumping into building a machine. Since you are a student, if your campus has any CNC equipment anywhere you may want to see if you can get access to what they are using for CAM software. Since it can be so expensive you may find its only installed on one or two PCs tucked away in a fabrication lab somewhere.

Definitely get a drill press! I would consider it almost necessary. If I had to only have two power tools to build this, they would be a drill press and circular saw. If I had to eliminate one of those, it would be the circular saw. I used a cheap $100 Home Depot drill press, with a cross-slide vise from Harbor Freight. After building two machines, my primary memory is of drilling lots and lots of holes. Trust me, you'll want a drill press. If on a budget, scour Craigslist for a used one.

-Bob

[GTFreeFlyer]

For those of you who are more visual, such as myself, here is a chart from my spreadsheet which contains more than 100 line items, all categorized. Keep in mind my software cost will probably skyrocket once I decide on a CAD/CAM package. For now I've only bought a Mach 3 license so that I can run G-code from the trial software I have. I must say, I am liking CamBam. I do plan on making 3D parts, so I will eventually need something else, but I'm sure 90% of my work will be more than fine with CamBam's functionality. I found it easy to use and it was the first CAM i started paying around with. I have about 25 uses left before I'll need to buy a license. They allow you to download it free and it is completely unlocked for the first 40 times you open the program.

[evengravy]

I'm coming to the end of my build of a version 2. My total is coming in at around £1100 uk. Metals and fasteners cost quite a bit more here than in the us, plus most things are ordered online which accounts for a good fifteen percent of the total. Bear in mind I used marine grade plywood and high quality motors and my build is slightly larger than standard.

[cgodwin]

With mid-range electronics, but no software or tools, it looks like I'll be around $900 when I'm done in a few weeks. I added 12" to my X axis, so that added a little - maybe $50.

Not included in the $900 is the SuperPID controller, which I haven't used yet, but I hear it is a great addition at about $150.

Fortunately I already had all the tools I needed, including a drill press which really is necessary. I found a band saw was extremely helpful for cutting the aluminum parts also.

Eventually I'll need to spend a little money on software, as I haven't found free software yet that seems like it would work. It would be easy to spend far more on software than the Momus costs, but it looks like you could get setup pretty well for $300-$500 depending on what you want to do.