need more Z

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SnaykeByte
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Model of CNC Machine: Shark Pro

need more Z

Post by SnaykeByte »

I want to use a vacuum clamp system but I don't want to give up 2" of my already meager 4.5". Sooooooooooo, is there a feasible and affordable way to increase Z? Longer gantry supports maybe? I'm only looking for a couple more inches so I don't thing it would increase leverage or unsprung weight and cause the whole machine to flex excessively. Thoughts anyone?

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martin54
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Re: need more Z

Post by martin54 »

Raising the gantry on a machine by 2" can have an enormous effect on the rigidity of a machine, it would obviously be dependant on the current set up of the machine & how you intended to increase the gantry height. Also depends what materials you machine. If you think 4.5 inches of usable height on your machine is bad then you want to try using mine for a week or so. Would make you appreciate the height you have lol. I have less than half that on my machine & yes there are a lot of things I would like to be able to do but can't. Raising the gantry is possible, have seen a couple of machines where it has been done so maybe something for the future.
If your looking for a vacuum hold down what about something like vacuum pods which are pretty low profile. Mine are about 12mm in height manufactured from cast acrylic. I've made them at various sizes & can string them together if I need to cover a larger area.

weber765
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Re: need more Z

Post by weber765 »

Just a thought, but could you lower your bed and increase your z travel ? When I built my first machine I made it so I could actually drop my bed 28 inches and I have 8 inches travel in my z axis. This would help keep your gantry more rigid.

PaulRowntree
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Re: need more Z

Post by PaulRowntree »

SnaykeByte wrote:I want to use a vacuum clamp system but I don't want to give up 2" of my already meager 4.5". Sooooooooooo, is there a feasible and affordable way to increase Z? Longer gantry supports maybe? I'm only looking for a couple more inches so I don't thing it would increase leverage or unsprung weight and cause the whole machine to flex excessively. Thoughts anyone?
2" seems pretty thick, but it depends on the design. There are slimmer versions, such as a array of holes in a double-sheet sealed MDF plenum, probably less than 1" thick.
Paul Rowntree
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martin54
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Re: need more Z

Post by martin54 »

weber765 wrote:Just a thought, but could you lower your bed and increase your z travel ? When I built my first machine I made it so I could actually drop my bed 28 inches and I have 8 inches travel in my z axis. This would help keep your gantry more rigid.
It's relatively easy to build in a Table with adjustable height when you are building a machine from scratch but I am guessing it is a bit more of a problem when trying to fit one to a manufacturers existing machine, would be a better option than raising the gantry but not as simple to do.

SnaykeByte
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Re: need more Z

Post by SnaykeByte »

I think I'm gonna order some vacuum pods and seal my table, that'll gain me 1 1/4".

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scottp55
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Re: need more Z

Post by scottp55 »

Read up and then make your own pods...You'll learn more and get better ideas on your own personal needs.
My first was maple and Frost king weather stripping and taught me a bunch.
Better quality can be found many places, including AllStarAdhesives:
http://www.allstaradhesives.com/
On/in/cover and George is VERY helpful.
Just saying you don't need to reinvent the wheel.
scott
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Leo
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Re: need more Z

Post by Leo »

I just changed my "Z" from 4" to 10"

All I had to do was wire a boatload of money to China.

----------------------------------------------------------------

Previously I was planning to make new gantry sides and gain an extra 2" to give me 6". Any more and I would sacrifice too much rigidity. I never got to that point as I got such a great deal on a new machine. I would do it though, just don't need to now.
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

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martin54
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Re: need more Z

Post by martin54 »

Leo wrote:I just changed my "Z" from 4" to 10"

All I had to do was wire a boatload of money to China.

----------------------------------------------------------------

Previously I was planning to make new gantry sides and gain an extra 2" to give me 6". Any more and I would sacrifice too much rigidity. I never got to that point as I got such a great deal on a new machine. I would do it though, just don't need to now.
Leo, do you know the conversion rate?? I'm in the UK so things are a bit different, how many shedloads of money are there in a boatload??

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Ms Wolffie
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Re: need more Z

Post by Ms Wolffie »

weber765 wrote:Just a thought, but could you lower your bed and increase your z travel ? When I built my first machine I made it so I could actually drop my bed 28 inches and I have 8 inches travel in my z axis. This would help keep your gantry more rigid.
That is not possible to do on the Shark but what I did was replace the gantry backing with a thick checkerboard aluminium piece and narrow the depth til just under the lowest screws on the gantry sides.
The router lifts high enough to do this and you gain a few inches.
Also the checkerboard is much more rigid than the original backing board.
I'll post a picture when I find it on my PC.
Edited:
I just realised that you have a Shark which is quite a bit smaller than my Pro Plus HD, so the conversion will be a bit different.
Shank CNC.jpg
By replacing the backboard with an aluminium plate, you are increasing the rigidity of the gantry and will be able to lift the sides to their highest settings.
If possible, I would add an aluminium plate to the sides as well but that depends on your ability to get them cut.
I have remade mine in 1/2" aluminium plate on the side of the gantry and the router lifter and reinforced the base with 1/4" checkerplate.
I have also replaced the bearings with adjustable ones.
Was a big job, but worth it in the end :D
Cheers
Wolffie

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Leo
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Re: need more Z

Post by Leo »

Just a bit off topic - but those hold down clamps are backwards.

If you turn them 180 degrees you will get multiples more clamping force.
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

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Ms Wolffie
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Re: need more Z

Post by Ms Wolffie »

Leo wrote:Just a bit off topic - but those hold down clamps are backwards.

If you turn them 180 degrees you will get multiples more clamping force.
But......
then they would be too long for the slots in the table :lol:
Cheers
Wolffie

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