[Hack]

I was reading a few threads around the zone and one that interested me was on about and "open source" mill design where the guy(s) were designing a set of mill castings and were going to build and "Made in North America" mill. Well that has gone on for over 2 years and well....nothing. I wish the author luck as I liked the design and concept, but I am tired of waiting to see if it will produce anything.

So I decided to start an adventure of my own. I am starting to build a homemade cnc mill including castings. The mill will use 20mm linear slides, ballscrews and have travels similar to a SYIL X5. Spindle will either be R8 or BT30 and should be a fun project.

I have started with the castings. I need to make a set of them out of wood and then I will take them to a local foundry to have them pour a set. Today I glued up a buch of MDF, and tomorrow I will start routing the patterns on my CNC ROuter. The base is going to be 10" x 20", The column 7.75" x 24"

Not much for pictures, but I have to start somewhere.

Dan

[mountainbarn]

I have been collecting parts for a similar project.
I have so far got the slides (25 and 30mm) a 6.5" x 21" table
(part ordered from grizzly for one of their mills), and a
machine head on the way.
I was trying to decide between castings or laser cut plate
for the base and column. My neighbor has a cnc router, so I was considering
doing castings as well. My thoughts were to possibly make a manual and a CNC
version, but that is up in the air.

Cheers:cheers:

[asuratman]

Hack,
Do you have picture? Your column height is 24", is that short?

[mactec54]

Hack

This is a good build to,from scratch, with patterns, & casting, But has not posted while

http://www.cnczone.com/forums/vertic...c_machine.html

[Hack]

The column is only 24", but according to my drawings it should give me about 10" from spindle to the table along with a corresponding 10" z travel.

Attached is a PDF of the design. It is not completely detailed out, but should give you an idea of what I am working towards. Most likely I will make everything out of mdf before submitting a final design to the casting company.

I am planning on getting out into the shop today to do some routing on the blanks I glued up yesterday. I'll take some pics of the progress.
Dan

[Hack]

Well I got out to the shop and put the router to work today. Needed about 2 hours of spindle time to get these done, but they turned out pretty good. The first few pictures are of the items as they are on the router and the last few are semi finished and shown in mock-up form. Should give everyone a good visual.

I will be added a few "raised" areas on each casting for machined surfaces. Areas such as where the linear rails will bolt on and where the ball screw end supports will mount. That should minimize any machine work afterwards to those areas only.

Enjoy.

Dan

[slowlearner]

Nice and heavy, I'm looking forward to this.
Thanks

[jharvey407]

Dan,

I will be watching this thread with a lot of interest. I plan on building a CNC mill eventually. I'll be trying the epoxy/granite route for the castings, but my design will be very similar to yours.

I need to get my router finished first. The router is actually running and producing billable work, but isn't quite finished yet.

James

[Hack]

Feeling a little embarrased right now. I went back a looked at my CAD Model and realized the the back was drawn 4.5" thick, not 3.75" thick like the base is. When I glued up the material, I made them both the same.....I was wondering why some things weren't lining up just right.

Oh well, tomorrow evening, I will glue another layer on to the back and Tuesday (after the glue dries), i should be able to route it out and make it right. Wont change the design any, just make it heavier .

Dan

[PEU]

one suggestion to make it a lot stiffer, widen the base halfway to the backside and also add supports to the column, check images:




How do you plan to machine the parts after casting?


Pablo

[mountainbarn]

Just a new guy here, maybe i can not tell from the pictures, but should the
molds not have angled cuts so the mold can be pulled out of the sand without
disturbing the sand?
Looks good so far.

Cheers:cheers:

[Hack]

Well I got another layer of MDF glued on tonight. I'll let it dry overnight and finish it up tomorrow evening.

PEU - Love the picture but shhhhhhh...(that's my secret second design I'm working on). Well not exactly, but using some of the concepts you suggested. That will be a bigger machine for another day. I will machine these "smaller" castings on my current mill - See pictures attached.

Mountainbarn - I was actually thinking the exact opposite, that you WANT a taper to allow the pattern to release from the mold. Oh well, that why we are making MDF patterns. I'll take them to the casting place and let them suggest changes.

Thanks

Dan

[Hack]

Well I got a bit more done tonight. I was able to finish fixing my minor mistake on the column. Turned out well so that is now a non-issue.

I routed out parts tonight to mock up the housing for the spindle. CNC Routers are Nice!!! :banana:

I didn't get them glued up, but have them clamped to show everyone what they will look like when finished. Hopefully I will get them glued up tomorrow. In the picture, they parts are upside down from thier intended orientation. I also need to do the finishing touches on the base and column.

My goal is to have the parts ready to take to the casting company sometime next week.

Eye candy is attached.

Dan

[DSpeck]

Did you make the hole for the spindle undersized to allow for machining to final dims, including the flange recess? That can be something to be careful of.

Since you are designing from scratch, have you thought about way-covers and swarf control? With the pre-made mills, this may or may not be taken into account, but you can add in room to allow for this from the beginning here. It will save you grief later, I'd think.

[LUCKY13]

This is pretty cool, have got any idea what they will charge you to cast these for you?


Jess

[Hack]

Yes, I have given some thought to bellows and swarf control. The rails are positioned an appropriate dimension to allow an off the shelf set of bellows from McMaster Carr or MSC to be used. I went down this road with my last mill and it was not fun. I didn't plan ahead and ended up rigging up something to make it work. Not ideal.

The spindle through hole is just a bit bigger (.030) then the spindle itself. The counterbore is the only area I will be machining (other then the back to ensure flatness) and it is a bit shallow and small in diameter to allow machining in both dimensions. My intended spindle is an off the shelf unit with a 6 bolt hole pattern for mounting. I want to machine this area for flatness as I know the casting itself will not true enough for a spindle. I will want to true it up with the back of the casting to make sure it is mounted parallel to the ways when done.

No I am not sure what it will cost to have these cast. In quantities of 1 they wont be real cheap, but maybe multiples will be better. Maybe I need to build a couple dozen just to get a price break on the castings? Think the wife would go for it?

Dan

[zephyr9900]

Dan, are you planning to core out the head casting behind the spindle? Keeping that solid will make for one heavy head. Or are you taking care of the coring separately? With your laminated pattern construction you could make slices like my attached butchery/markup and leave a couple solid (well, partial-thickness pocket for proper web thickness) for cross-webbing. Of course, my opinion is worth what you've paid for it.

That's a neat looking project, and neat also to bootstrap by using the CNC router for the patterns.

Randy

[Hack]

Randy,

I can honestly say I have not given much thought to the need to lighten the spindle housing until you mentioned it. I used an online weight calculator and I see I am looking at around 75 pounds for that little bugger less the area for the spindle. But even then adding back in the spindle itself and 80 lbs is not unrealistic. On my current mill, I was approaching 100 lbs and ended up adding a couple of hydraulic cylinders to counterbalance the weight. I really do not want to do that again. I will give this some consideration - thanks Randy.

I was able to route out a makeshift table tonight. it is 7" x 22" x 1 1/2". I had a bit of a goof up with the router (operator error) and took a nice slice out of the top. Oh well, that's what wood putty is for. I am going to price getting the table cast (and ground) and I will do some machining of the t-slots (cleanup as needed) I didn't have a t-slot cutter for the router so it is only slotted right now. Pictures below.

What I have made so far is the 4 parts of this mill that I want to have cast - Now I just need to decide what modifications (such as lightening) I will make before going to the casting company.

In the mean time, I am thinking about making some mockups of the linear rails out of hardwood to simulate and verify travels, clearances, etc.

Dan

[DSpeck]

Randy - Good catch on lightening the head - I didn't think of that.

Dan - to make the hole for the spindle while making the back of the part hollow, I think they will have to make a sand core, since the spindle hole is perpendicular to the back. This may add to your cost. If you can make a mold for the core, I think it would help to reduce this additional cost of the casting. They use CO2-hardening sand for these, but I don't know what provisions you'd have to make in the mold for that process (pinholes in the sides to allow the CO2 in, maybe?).

As for the table, you wouldn't want to mold in the T-slots, as they couldn't be pulled out of the sand cleanly. Undercuts don't work in casting, from what I've seen. I would suggest that you allow about .060" or so on each surface to machine away any inaccuracies and skin effects in the casting, with a 5 degree draft angle in the slots to allow it to form the sand mold correctly.

Just thought of another thing - what are you doing for a saddle? How will you connect the X and Y axes?

I'm fascinated to see this process, and I want to help make it go the best it can!

[rocketflier]

Very cool! Was following someone overseas building a mill, but he seems to have disappeared. I think he had sent the plugs to the foundry.
http://www.cnczone.com/forums/vertic...c_machine.html

Don't know if you've followed any of the concrete/epoxy threads? Basically molding a machine and filling the cavity with a stone/epoxy mix. The rails possibly included at pour time or inserts placed in the cavity to allow attachment after cure.
Epoxy Granite - CNCzone.com-The Largest Machinist Community on the net!

[edit] epoxy spindle:
http://www.cnczone.com/forums/open_s...ild_using.html