slim-size spindles on Z-axis ??

Hello from The Netherlands,

I am in progress of designing a (home / business) build router/milling machine which can handle our standard size 122 x 244 cm’s ( approx.: 4 x 8 foot) plywood boards.
The footprint of this machine will measure 200 x 300 cm’s ( 6foot5 x almost 10 feet)

Normally the usual Z-axis constructions allow the tool to be moved to a maximum of about 4 inches, that is OK for ‘normal’ router jobs, engraving and even relief-milling.

My problem is the fact that we also want to machine some materials like PU-foam, balsa or other “easy to mill” media to create solid models of model-boat-hulls ( to be used for polyester mould making, professional maquettes etc.)
The problem is that we need a much larger movement of the Z-axis (read: tool) of up to 8 or 10 inches AND that the fixture of the router-motor prevents the milling of the near vertical lines of such models. (see picture attached)
Part of the last problem can be solved by using a larger tool-diameter but this is not always possible, a longer tool will become unstable when run on higher speed.

I am now thinking about building my own “slim-sized” spindle of 1 inch in diameter with a solid steel drive-axle inside driven by a motor which will be mounted on top of the Y-axis construction.
The spindle will be retracted completely inside the Y-axis construction when in upper-position to free the 8 or 10 inch space under the Y-axis construction.

Before I start ‘inventing the wheel’ again I would like to know if there is anybody on this forum who has already solved this sort of problem or knows a company who has a ‘slim- spindle” already in their program.

Any feedback and ideas on this matter will be highly appreciated.

Thanks in advance

John van Gent
CAP Maquettes NL
www.cap-maquettes-nl.com

Hi,

I saw something just the other day on ebay that seemed to fit your description. It was a long spindle housing, probably 12 inches OAL. No motor at the end. It probably held 1/4 inch bits. It looked like it was designed for high speed applications. From what I remember reading, it was made for jig boring, and it was extra lond so it could reach deep inside tight spaces. It looked to be about 1.5" DIA. I've looked for it just now but haven't seen it.


You could try googling "jig grinding spindle" or just "grinding spindle".

You might also consider these:

http://cgi.ebay.com/taft-peirce-grin...QQcmdZViewItem

http://cgi.ebay.com/KaVo-4041-HIGH-S...QQcmdZViewItem

Carlo

Maybe you could go to a fourth (rotating) axis. Ive seen alot of those type's of aplications done that way, by rotating the spindle or the work. Another way is with a rotary table. Something to think about.

Die grinder

Quote:

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Originally Posted by capnl

H

I am now thinking about building my own “slim-sized” spindle of 1 inch in diameter with a solid steel drive-axle inside driven by a motor which will be mounted on top of the Y-axis construction.
The spindle will be retracted completely inside the Y-axis construction when in upper-position to free the 8 or 10 inch space under the Y-axis construction.
John van Gent
CAP Maquettes NL
www.cap-maquettes-nl.com

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Hi John,

It happens only a few times in a persons life. That moment of brillance! I think you have had such a moment. The retractable spindle idea is great. I suggest that before you do anything else with it that you protect this idea till you find out if it is feasible, and if it is then find out if it has been patented.

Mike
ps I want one!

John,
I have a router of the size you mention that I use to form foam patterns for casting my metal sculptures. One recent piece was a 3'x3'x2' (~914cm x 914cm x 610cm) horse head in cast iron weighing 300 lbs (136kg). I don't have a z axis that will handle this. My answer was to slice the computer model, router the layers out of 2" thick (~5cm) foam, and then glue the layers together. It worked well.
---Sculptor

Quote:

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Originally Posted by Sculptor

John,
I have a router of the size you mention that I use to form foam patterns for casting my metal sculptures. One recent piece was a 3'x3'x2' (~914cm x 914cm x 610cm) horse head in cast iron weighing 300 lbs (136kg). I don't have a z axis that will handle this. My answer was to slice the computer model, router the layers out of 2" thick (~5cm) foam, and then glue the layers together. It worked well.
---Sculptor

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Nice work.

How many slices did you use? How did you keep your sanity?

-Nice Work.
---Thanks.
-How many slices did you use?
---12
-How did you keep your sanity?
---You ask this of an artist???

Sculptor

Depending on your cadcam system, it might be worth it to plan to make your table as a simple indexing unit. By this, I mean a tilting yoke sort of construction that would allow you to pull a pin, and tilt the table, by a fixed increment of degrees. Then, tilt the model in your cadcam to expose the side of the model in the new position and 3d machine it. I'm not thinking of only face milling large flat areas (which would require exact angle setting), but rather to bring the required Z depth and surface access to a more reasonable distance.

By incorporating elevating mechanisms (like a knee mill table), you could bring the work zone of the table within reach of the spindle.

Basically, it would be like a poor man's 4th axis, without the expense of making a huge rotary indexer.

Hello to all,

first of all thanks for all support and ideas so far !!

for those who wonder what I am thinking about, here are some simple drawings.

material to be used steel square tubing, mainly 50 x 50 x 3 mm (2" x 2" x .125") except for the (light blue) 3 meter long support for the Y-axis-construction wich will be 50 x 50 x 5mm ( 2" x 2" x 0.2") all connections will be welded.

red: 1 meter (40 inch) high legs, (8 needed)
green: connection between legs in X and Y direction (cut to size needed)
dark blue: 3 meter long bed-support in X-direction
black: 1.90 meter long bed support in Y-direction and connection between the legs in Y-direction
grey: 2 meter long bed support in Y-direction wich also will support the 3 meter long support for the Y-axis-construction
dark-green: vertical support legs (cut to size needed)
light green: wooden bed 50 mm multiplex (2" ply) to support the "offer-material" wich will support the material to be machined.

I have made calculations for the weight of the total construction it came out on approx 400 kilo's (1000 lbs) so this one will not walk trough my workshop that easily.

(yes I have the lifting capacity in my workshiop ;) )

I hope this onfo will be of positive contribution to other DIY-builders

Greetz,

John

Quote:

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Originally Posted by Sculptor

John,
My answer was to slice the computer model, router the layers out of 2" thick (~5cm) foam, and then glue the layers together. It worked well.
---Sculptor

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Hello Sculptor,

I have been considdering the 'slicing' of the model and it will work for me very well, but the challenge for me is to create a solid (foam)model with the 3-axis machine wich otherwise would probably be machined on a 5-axis machine, but unfortunately no $$ (or €€ in my case) available for that. :(

Any chance that we can see more pics of your work (your website??) and machine you use ??

Thanks for your contribution.

John

John,
I don't have my own machine as yet, but have after-work access to a ShopBot 3 axis machine. This is why I've opted for the layered approach and why I completely understand your desire for a machine that will handle a larger chunk of material. I am working slowly (very slowly) on building my own machine from scratch, but that is for a later date. No website as yet. As for my work, I'm in the process of photograghing a few pieces and will try to post soon??? In the meantime, here's a print of the Hoss sliced up.

Quote:

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Originally Posted by Sculptor

John,
have after-work access to a ShopBot 3 axis machine.

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Hi Sculptor,

:cool: Wishing I had that kind of access...... :cool:

It is the SHOPBOT machines that are my favorite but the price and shipping to Holland made me decide to start building my own with their machines in mind....

About slicing:
for me slicing a model of a ships hull into a left and right-hand side is also an option, normally a mould is made that way.

John