[lcvette]

I have been presented with a unique opportunity to design a machine to be produced by a machine manufacturer (no affiliation whatsoever) and would like to share this opportunity with a group of people who may also be interested, who have design experience, and are interested in a collaborative design project resulting in an actual machine that would be available when finished at a reduced price for the design work out in. The plans would be the property of the manufacturer at the end of the project and they would manufacture and sell to the public. This seems like a good opportunity to finally have a machine with what we all here seem to want from what I have seen in

As I'm sure many of you have experienced, After a long time (5 years) of using a cnc G0704 and considering upgrading it further, converting other machines or a scratch built mill from steel or epoxy granite, I always wound up finding myself compromising the desires of a small converted mill or snapping back to reality the reality of an intensive multi year long build and not wanting to commit to such a project and switching gears and looking at VMC's which of course have all the features desired, but present their own list of obstacles not the least of which is a giant up front cost.

This led me to begin researching and reaching out to various machine manufacturers in China for an alternative of which I found a few but always with subpar travels for the expense, albeit having most of the other desired features.

After long discussions with several of these manufacturers, I found one who impressed me very much, had VERY reasonable pricing, and who was the most willing to be flexible in modifying their existing machines to suit my criteria. After much back and forth discussion and pictures and design considerations on my end.. The manufacturer suggested that changing an existing machine may not be the best course of action and offered to build a new machine based on my designs. I considered this for a few weeks and then thought that it may be worthwhile to expand the thinking on such a machine to a broader input group so maybe it benefits the forum members more.


So, here I am, requesting some other forum members who are looking for more then whats out there and less then a full blown vmc. The goal will be to design a new machine to be cnc ready and/or offered to varying degrees of completion for a DIY. This will be a machine a little more suited to production then what is currently available in the small mill category. The machine design will have a compact layout and minimal footprint and required access space. It will not be as big and cumbersome as a full VMC and will solve the issues they come with such as 3 phase requirement, giant space requirements.

The new design should have easy access to components for servicing, access from the front or sides of the machine for electronics and coolant system and chip management. Machine should be Manageable with a pallet jack and freight truck lift gate for easy delivery, fit through a 8' garage door fully assembled with head down and blocked and 7' garage door with minor components disassembly. Complete with all components for DIY assembly for motors, wire management etc.

Other Design criteria I have come up with after a lot of searching and research and personal experiences are as follows, and of course as a collaborative effort, completely open for discussion.

- BT30 Spindle ATC type w/ pneumatic drawbar and belt drive system and motor provisions (seems to be the best compromise between cost, rigidity, tooling costs)

- Travels X-30" Y-15" Z-20" with all axis quality hiwin linear rails

- Table size 12" X 46"

- Ballscrews P4 C5 double nut ground

- Automatic lubrication system

- Way covers

- Modular enclosure for toolroom or fully enclosed design with upgradable option

- Positioning accuracy .02mm (.0007"), repeatability .01mm (.0003")

- Automatic tool changer (12 tool carousel exists already, if an arm type is desired will need to be designed)

- Electrical design and layout for cabinet. Provisions for powering a 5hp vector duty motor with VFD drive with spindle indexing, Axis servos /Steppers and drives, axis home and limit switches, power drawbar, automatic lubrication system, 4th and 5th axis expandability, ATC, Probing and tool setting, glass scales (possibly?), Lighting, washdown, chip conveyor, anything else I may be forgetting or not considering.


I'm certain I have left out items but that is where many minds will prevail. With fusion360 available for the hobbyist at no charge it seems like a good platform to develop the machine design in and collaborate in. I personally have little experience with fusion and use solidworks which I am proficient in, but luckily most everything is compatible now days so those like me with solidworks background aren't left out.

So lets start this discussion. From my length of time of discussion and many many requests and persistence I have a been given direct access to the manufacturer tiring companies, CEO who can help guide the design process by critiquing the designs based on manufacturing difficulties that will drive costs up. His company has been manufacturing machines since the mid 1950's and he brings a wealth of first hand knowledge with regards to casting and machining the components of the machine design.

It really is one of those rare instances where we get to make something we actually want rather then be constrained to a companies ideas of what we should have. The one caveat is that we will need to have a group who will be interested in purchasing the machines when completed. They would like to see at least 10 machines but are flexible and easy to work with. Based on their other pricing I have been given, I think the costs will be lower then what one would expect, and we can get some rough estimates early on in the design phase and use them to guide the machine designs to stay within a certain budget and make items optional so as to keep the modular concept working to allow initial costs to remain low but have expandability down the road.

So who would be interested in such a project?

1- Chris (Lcvette)
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Chris



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[ianagos]

Well I'd like to help but I am not very efficient with cad I have solidworks.

[robertk925]

I am interested.

[lcvette]

Ok excellent, looks like a start! I suppose lets brainstorm on any features and benefits I have missed in title thread and I will update the first post as they are added so it will become the "Master" build criteria.

Not being an avid Fusion user, Hopefully someone who is familiar with fusion and its collaborative features can chime in? I can post the solidworks files I come up with in this thread or upload them through fusion.

To start off the design thoughts, in order to keep costs low I have determined the best design will incorporate a long table and short saddle very similar to the Haas TM2P. It utilizes linear rails on the table bottom and the bearing blocks are attached to the saddle. This also reduces parts required for way covers on the sides of the table.

Attachment 304050

It also gives a longer table for using multiple vices and a rotary table or Lathe head if so desired.

The base and column configuration is always fun to layout due to the saddle linear rails covers, and column way cover, this will require some thought and planning.

So bring your ideas and lets start formulating a game plan to get the designs rolling!!

Chris

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[ianagos]

Well I see why you say is better to have the rails attached to the bottom of the table. But I do think that it's a better design to have a wide saddle with the rails on there and the blocks on the table. I think this will help with rigidity on a smaller machine. For a little extra space on the table it could be made like sort of a T shape.
For the linear rails I suggest the RG series hiwin or the QR series this will greatly add to the rigidity. Ill post more stuff as I think about it.

[ianagos]

[lcvette]

Ianagos,

I have drawn up both styles and I agree on a larger machine a heavier Y axis saddle makes the most sense. However, the costs associated with that style add up very quickly. We can certainly submit a design for both for pricing purposes.

However as far as rigidity is concerned, I don't think it will be a major concern. A rail on table design is very rigid as the supports remain in a square formation with the spindle cutting force centered between the bearing car location.

I think the larger Y saddle is mainly used to increase the table load capacity significantly. Primarily when spreading the load out significantly with extra long X travels. We can put a few design versions through simulations to see where the advantages become evident and make a determination on cost vs benefit.

For 30" X travel my guess is there will be some benefit but the costs will far out way it. But the proof will be in the design FEA sims.

I guess a good data point would be to determine the max weight on table to determine what is needed to accommodate it. I doubt I will put anything over 300-400lbs on a mill of this size, but then again I would like to hear what you all would want it to be able to handle.

On the rails, I agree 100%, I think RG style pin rollers are the only way to go. They have more bolts per length in the rail as well which adds rigidity on a linear rail machine.

I'll post an edrawings file in a few minutes..



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[lcvette]

Going to try and see if I can attach these files... you will need edrawings to open and view them.. ok, had to zip the file to allow it to upload! good to know for future reference!!

try that!

Chris

[ianagos]

Ok I'm going to get on my laptop I think I have e drawings. It comes with solid works right?

Edit what year solid works do you have? I used to have 2012 but just got 2016
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[lcvette]

I have 15

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[ianagos]

How do i post a drawing as an edrawing thing im not very good with the solidworks.

[lcvette]

You just go to file tab and on the list there is an edrawings option

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[ianagos]

sorry i was being stupid then i messed up (actualy modeled table with t slots and mounting locations then i was gonna add some kurts lol but i dont realy know how to assemblys) so i just mocked up a simple thing of how the table would be better i think. i think it would be possible to squeeze a little more table size out of it.

hey i got it on edrawing and saved it as a zip file but its too big to poston the forum, how did you get yours so small?

[lcvette]

sorry i was being stupid then i messed up (actualy modeled table with t slots and mounting locations then i was gonna add some kurts lol but i dont realy know how to assemblys) so i just mocked up a simple thing of how the table would be better i think. i think it would be possible to squeeze a little more table size out of it.

hey i got it on edrawing and saved it as a zip file but its too big to poston the forum, how did you get yours so small?

Not sure, it just is the size that it is..lol. It should be quite a bit larger than yours considering it is an assembly. Did you save it as an edrawings file? And then zip the edrawings file?

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[lcvette]

You can email it to me if you want..

[email protected]

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[ianagos]

when i did that it came out 15mb for a very simple shape i didnt realy understand.

[lcvette]

You saved it as an IGES file.. That is why.. E drawing won't open it on my tablet, try going to:

File>publish to edrawings

That should open it in edrawings. Then save it in edrawings. Find the saved file on your hard drive and zip it then upload it here, that is how I did it. Works fine! I can't open it as it is.

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[lcvette]

I went to my workstation. And opened it, I see your intentions, but not sure if you mean to out the cars on the small of the Tee or in the cutout recess. Guessing under the small of the Tee, however that is just really adding alot of mass to the table. May as well just make it single level and extend it, still going to be a diving board unless it is really thick. That was why I put my trucks closer to the end to enable a lighter table with 3 tracks making 3 support points which will reduce harmonics in the table and add stiffness to the ends of the table.

With the rail in table design this isn't a concern as much because you are always machining between support points.

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[ianagos]

No i tried doing it as edrawing. but i opened it in e drawings. ill try to just save strait from solid works in the e drawings file type. also id like to ask if you have another type of file you can send to me because the edrawing file type has no dimensions to it so its very had to realy see what im looking at.

sorry took me so long to figure that out i had exported it to edrawings and saved from there what i had to do was save as a edrawings file directly from solidworks.

edit another mention id like to make is with a table like the the motor can sit close on the sadle making less stickout if you can find an appropriate motor.

[awerby]

So how will this machine be different from other smallish knee mills? Is it going to have an epoxy-granite frame, more Y travel, or a 4th, 5th, 6th axis? A faster, more precise spindle that still performs well at low RPMs? Will it be able to make parts that existing mills can't make, or just be cheaper to build than normal mills? Does it take advantage of any technological breakthroughs that aren't embodied in current mill designs? Will it have a different control system? 3 phase electricity is necessary for most spindles, but if they aren't too big it's possible for inverters to produce it from single-phase. Is there a target weight?