Water or Air Cooled Spindle

Tundraman
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Re: Water or Air Cooled Spindle

Post by Tundraman »

Stargeezer,
Thanks for the info.
I got a new to me machine :D , (used) so it saved time for building a new one. Still getting things rearranged in the basement, this one is much bigger than the old one. However the one I got has a router, so I will still be looking to upgrade to a spindle in the future.

Ms Wolffie,
A gas spring is basically a shock absorber. Like the kind used on the rear hatch of minivans and SUVs. In the states they are available from a number of places starting at 15 lb lift and up in many different lengths. Some from auto supply companies or factory/industrial suppliers.

I have not installed any but the machine I just got has one installed. I'm trying to get my shop rearranged, etc. so I can get it running to try it out.

Hope that helps get a better idea of what was meant.

Thanks,
Scott

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Ms Wolffie
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Re: Water or Air Cooled Spindle

Post by Ms Wolffie »

Thank you Scott :D
Cheers
Wolffie

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armbrusterco
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Re: Water or Air Cooled Spindle

Post by armbrusterco »

Wolffie,

Here is a link to the McMaster Carr webpage. http://www.mcmaster.com/#gas-springs/=zb8ypz The capacities range from 15 to 250 pounds.

The gas spring with ball joint fittings was pretty easy to mount on the Z axis. It took some figuring to work out both the compressed length and the extended length so I could order the right one. I weighed the Z axis and spindle components that moved in order to estimate the weight capacity of the spring. I found the actual dimensions matched those on the website.
Bob Armbruster
www.ArmbrusterCo.com

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Re: Water or Air Cooled Spindle

Post by Nirbikulpa »

[quote="Ms Wolffie"][quote="armbrusterco"]You should not need air assist. Instead, I use a "gas spring with ball-joint fittings" form McMaster-Carr on my Z axis to offset the weight of the spindle. I chose a gas spring with "available force" similar to the weight of the Z axis and spindle added together, and a stroke a few inches greater than my Z axis movement. Not very expensive. No maintenance required.

Please could you post a pic of what your solution looks like after having fitted the gas spring? I am planning an upgrade to my cnc at home to a 1.5Kw water cooled spindle, but I am not sure if the alu extrusion currently in use - along with the mechanism being used (including stepper motor) would be strong enough to move a 4kg spindle motor without some support (like a gas spring) and I can't seem to figure out how one would fit something like this or even how to calculate what pressure would suffice. maybe it's time I purchase a better machine :-)

thanks for the help
greetings from South Africa!
Andre :-)

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Re: Water or Air Cooled Spindle

Post by armbrusterco »

Andre, I have retired and sold that machine to Scott. His username on the forum is Tundraman. I don't have any photos that show the gas spring, but maybe Scott will see this and upload some.

I have found some images on the internet and have attached them.

HOW TO SIZE THE GAS SPRING?
You are only offsetting SOME of the weight moved by your Z axis motor, so you don't have to determine the exact weight. You want a gas spring with "available force" or capacity slightly less than the total weight of the moving components of your Z axis. You have to estimate it or weigh it. If you can let the Z axis drop freely, you could use a digital scale. If your spindle weighs 4 kgm, perhaps add another 3 kgm for the mount for a total of 7 kgm and choose a gas spring near that. Even if the gas spring capacity is 4 or 5 kgm, it helps pick up the weight of the new spindle.

You also have to figure out the length of extension you need in the spring to handle your Z axis travel. My spring was vertical so I bought one with a little longer extension than my Z axis travel.

HOW TO ATTACH THE GAS SPRING?
The attached images show the gas spring with ball joint ends. The gas spring supplier should have options for different sized ball screw connectors that you can order. You can drill and tap a hole for the connector or drill a hole through a plate to use a nut on the other side of the hole. At the top end of my spring, I attached an aluminum extrusion and connected the gas spring with a t-nut in the extrusion.

You will probably have to make a bracket to attach the spring to your Z axis at one end or the other. Because of the ball joints, the alignment of the spring does not have to match the Z axis perfectly; the spring can even be at an angle as show in one of the attached photos.

After preparing the mounting locations or brackets, the ball screws are installed to the mounts. Then the ball joints on the ends of the gas spring are placed onto the ball screws. A lock-spring then snaps in place to keep them together.

Greetings from Chicago, Illinois, USA,

Bob
Attachments
Gas Spring Images.jpg
Bob Armbruster
www.ArmbrusterCo.com

Tundraman
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Re: Water or Air Cooled Spindle

Post by Tundraman »

Andre,
I will take some pics and post them. They will not be much different than the ones Bob posted for you. When I first heard about this I was over thinking it. It sounds much more involved than it really is. The information Bob included is very good and the pictures pretty much show they can be mounted in different ways - mainly whatever fits best for your machine.
Best of luck,
Scott

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Re: Water or Air Cooled Spindle

Post by Nirbikulpa »

Hello Mr.'s Bob / Scott,
Gents thanks a mill - the penny has dropped , I know exactly what you are saying and have some thoughts to complete the process. I've come to realize that owning a cnc machine is much like building a sand rail - there is always something that will change - next up I might add some branches and a turbo :-) speaking of Turbo, I have been trying to find guidance all over the web with regards to upgrades I am planning for my machine - the end result that I am after, is to be able to cut 10mm MFD with 1 pass, currently, I cat with 6.36mm bit @ .8mm passes, then the 1 nema23 starts heating up (after about 60min of cutting) jumps steps as ruins the cut completely.

Can you guys perhaps recommend somebody here that I can speak to to explain the current setup versus what I plan to upgrade to in order to achieve a particular result please.
this machine runs on Nema 23 stepper motors, a 730watt trimmer - it's most frustrating designing things, starting a cut, opening a beer and then to choke on that same beer when the steps starts jumping and ... I could get quite upset :x

essentially, this is the machine I have... (1m x 2m) it's slow, partly due to the low wattage of the trimmer - can't really set it any faster as the trimmer just doesn't have the power to cut at the same speed as the axis directs.


Guys, if you have any ideas who I can talk to about my upgrade ideas (stepper motors, stepper drivers and spindles) - please let me know as I desperately need some advice (email or skype)

Gentlemen, thanks a mill for your time taken to reply, for the knowledge you share freely, I appreciate it from a world away :-)
Hope you have a super weekend - if either of you own a sand rail - have fun!! :-)

Andre

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Re: Water or Air Cooled Spindle

Post by ger21 »

I would not waste the time or money upgrading that machine. It's really not much more than a lightweight hobby grade machine. Any components that you upgraded would expose the next weakest link in the chain, and there's really nothing worth saving.

The money would be better spent on a heavier duty machine.
Gerry - http://www.thecncwoodworker.com

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Adrian
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Re: Water or Air Cooled Spindle

Post by Adrian »

ger21 wrote:I would not waste the time or money upgrading that machine. It's really not much more than a lightweight hobby grade machine. Any components that you upgraded would expose the next weakest link in the chain, and there's really nothing worth saving.

The money would be better spent on a heavier duty machine.
+1

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Re: Water or Air Cooled Spindle

Post by armbrusterco »

+1

Andre, now that you are interested in doing more with a cnc machine, you will want to sell your current machine and upgrade. When you decide on the types and dimensions of materials you want to work with, look at machines with that capacity. You will then be much happier with the results.

When I retired, I sold my larger machine. Then, for my hobby work, I bought a small, high quality, lightly used machine on eBay that could produce small prototype parts in plastics and wax (models for casting parts). I understand the limitation of my machine and am delighted with everything I can do on it.
Bob Armbruster
www.ArmbrusterCo.com

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Re: Water or Air Cooled Spindle

Post by Nirbikulpa »

Morning to you all
Thanks Gents - for your honest feedback, as much as I hate to spend R90 000 for a machine 3 levels up from mine - it might just need to happen (things in SA are crazy expensive while out president has 734 criminal charges against him, does not help the rand $ exchange rate at all.

Ok, let's move those "wanting to upgrade" thought to one side - I have another question - perhaps somebody has come across this and can help....

I use GRBL Controller to send G-Code to the machine.
22 hour job started cutting, at hour 18, it failed with error "Unable to write bites to port probably due to outgoing queue full. Write data Lost!"
resulting in a 4cm hole straight through the waste board - I was a little freaked out about this... it's happened before - even on smaller jobs, COM7 is set to 115200 with hardware flow control (windows defaults)

anybody got any ideas what I can try to fix this perhaps please? while I think about an upgrade machine :-)

thanks a mill guys, thanks for your Help! I do appreciate it!!
Kind regards
Andre

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Re: Water or Air Cooled Spindle

Post by Ronnie »

What about the dust that gets sucked through the motor. Does it not block up?

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Adrian
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Re: Water or Air Cooled Spindle

Post by Adrian »

Ronnie wrote:What about the dust that gets sucked through the motor. Does it not block up?
On the decent spindles the fan blows through a heat sink jacket that surrounds the actual spindle so any dust that might be sucked in at the top doesn't go near anything delicate. It's not the same setup as a fan on a router.

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Re: Water or Air Cooled Spindle

Post by ger21 »

You should ask yourself why you have so much dust floating around 12" above your bit?
Even with the cheap round air cooled spindles, the air flows through the outside cooling fins, not through the spindle itself. The cooling channels are much larger than the intake slots, so you shouldn't really shouldn't see any dust buildup in the cooling channels. And fine dust should blow right through.
I do recommend blowing some compressed air through the cooling channles on a new spindle, especially the cheap ones, to remove any debris left over from sloppy manufacturing.
Gerry - http://www.thecncwoodworker.com

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