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  #1  
Old Fri 28 December 2007, 10:55
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
350mm [14"] Extended Z-Slide - what does it mean?

I am new here and to CNC. What it mean by 350 slide? Does it mean, it can cut a block of 350mm thk.? Or its just the travel of the router on the Z axis.

Thank.

Jksiew
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  #2  
Old Fri 28 December 2007, 12:04
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Where did you read "350 slide?" Was it written on one of the pages in the plans? If so, point us to it and we'll try to answer your question.
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  #3  
Old Fri 28 December 2007, 12:17
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
It is one of the option on the drawings. See dwg no. 10 00 000 (1st page of part 1).

Thank

JKsiew
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  #4  
Old Fri 28 December 2007, 18:28
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Arowana,

That is the amount of travel the Z Axis has if you choose to build it that way.
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  #5  
Old Fri 28 December 2007, 21:28
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
With that travel, I presume it can route a foam block of 350mm thk.

Thank Doug

James Siew
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  #6  
Old Sat 29 December 2007, 17:47
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
If you increase the size of the longitudinal beams so that a 350mm block of foam would fit under the gantry then theoretically, you could carve a block of foam that thick. However, other factors will come into play. Don't forget that the 4" wide Z-axis plate, router bracket, and router figure into the equation. In other words, pockets are going to be a certain minimum size. If you are carving surfboards with shallow curves then it wouldn't be a big deal. However, if you were carving a foam replica of a mountain range with steep slopes and rocky cliffs, it might not be able to do it. A longer router bit will help. How you mount your router will also affect the thickness you will be able to carve. For example, the face of my router collet is 2 inches below the bottom of my gantry. That's not a problem for me because I plan to cut mostly relatively thin sheet goods like medium density fiberboard.
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  #7  
Old Sun 30 December 2007, 07:19
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
If I build according to plan with the option of the higher X beam (see Dwg 10 00 000 with addition of 150mm), 350mm Z-Slide and a longer router bit, what is the max. block ht. it can carve ?

I am doing car body part, similar to the link below :-

http://www.k2cnc.com/EddiePaul.asp

Jk Siew
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  #8  
Old Mon 31 December 2007, 05:45
bleeth
Just call me: Dave
 
Florida
United States of America
Arowana:
Many people who have an extended z have found that there is a challenge in cutting thinner parts that are made of harder materials (like wood). For form work in foam remember you can always layer your model and cut it in slices. The other consideration in the extended z is obtaining bits over a few inches long. Most of the truly happy owners of extended z machines cut foam virtually exclusively.
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  #9  
Old Mon 31 December 2007, 10:25
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
My primary purpose for Mechmate is to carve foam (if I build one), if I need to cut thinner and harder materials I can always raise the table (or add) and have the z travel less. Is that possible?

Happy New Year to everyone here.

JK Siew
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  #10  
Old Mon 07 January 2008, 06:14
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by jksiew View Post
My primary purpose for Mechmate is to carve foam (if I build one), if I need to cut thinner and harder materials I can always raise the table (or add) and have the z travel less. Is that possible?
Yes, that is possible, and it is the recommended way - add a false table, or stage, on top of the "low" table.

350 is the millimeter equivalent of 14 inches. The amount of travel will be 350mm [14"], but the actually thickness of part that can be cut out is normally way less. Imagine cutting a bowl 6" deep with only a 4" long cutter protrusion......you must be able to lift this cutter over the edge of the bowl.......so you want 10" under the collet of the router.....

I added the 350mm [14"] option to show people what needs to be changed to get more z-stroke - you can scale further up if you wish, understanding the increases in flex. It would be a good idea to increase the under gantry clearance before extending the z-slide if you are going to have mostly long cutters - the basic MM design allows for the collet of the router to typically come close to the table.
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  #11  
Old Mon 07 January 2008, 23:08
kwang90020
Just call me: krod
 
California
United States of America
Gerald,
What do you think is best way to increase the under gantry clearance?
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  #12  
Old Mon 07 January 2008, 23:28
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Leave the gantry standard, but drop the table top further below the x-rails. Increase the height (and stiffness) of the main longitudinal beams.

You could even bring two longitudinals direct up from the floor - think of masonary walls - and have a range of "stages" that you could wheel into place below the gantry to give a range of table heights.
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  #13  
Old Tue 08 January 2008, 08:05
jksiew
Just call me: Arowana
 
Kuala Lumpur
Malaysia
What is the max. Z travel that can be build into the MM, if I use it for foam carving ? The design of the MM gantry look very sturdy to me.

Thank Gerald.

JK Siew
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  #14  
Old Tue 08 January 2008, 10:08
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Arowana, I don't know, because I havn't got experience in this area. Feel free to experiment.
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  #15  
Old Mon 09 June 2008, 14:01
orotemo
Just call me: orotemo
 
Warburg
Israel
Possible solution to flex in long Z axis?

Hi all,

Just a thought: Looking at the Z axis assembly, and reading all them posts speaking of the horrible flex induced, I decided to take a llok at the whole setup.

It seems to me that the only flexible part in the whole machine, is the spider plate, meaning: hardening the spider plate may increase rigidity of the z axis, thus enabling 350mm z axis with no flex penalty.

Ho can this be achieved?
  1. By raising the spider plate thickness a millimeter - limited added value - but still...
  2. by taking the finished spider plate, and welding some support plate on the back side, to connect car mount point of the spider to the center of the spider, a spider to self support.

What say you guys?
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  #16  
Old Mon 09 June 2008, 14:10
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
"horrible" ? not the description I would draw from the Z-slide discussion.....
"noticable" maybe - horrible....never.

...having run my machine an average of 4-7 hours a day for the past 5 months, I haven't noticed ANY noticeable flex in anything that isn't supposed to. If your going to used a very extended Z-slide....it should only be in foam or other material that is essentially "zero resistance" to the tool bit.
All the other machines that are cutting out there with very long tool bits are cutting foam or "foamlike" material because of the long moment arm induced by such a long z-slide.

...the main benefit I see from utilizing a machine like the MM, is the flexibility it affords each owner to modify for their uses. Long Z-slide is very very specific cutting. The normal moment arm of 8" on my machine cuts like a charm with EXCELLENT cut quality.

Good luck with your build should you choose to build one yourself.

Sean
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  #17  
Old Mon 09 June 2008, 14:25
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The "horrible" discussion is here. As far as I am concerned, it is a rumour until someone comes up with some proof in the form of measurements. If it is proved, the possible stiffener brackets are mentioned in that thread as well.

However, on Saturday I did change my copy of the drawing to state 5mm [3/16"] thickness. (it said 4mm [3/16"] before - the reported vibration was from a person with a 1/8" thick spider and a much lengthened z-slide).

Our 4mm spider is working perfectly.
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  #18  
Old Mon 09 June 2008, 16:00
dmoore
Just call me:
 
orotemo -

Maybe we should ask - how much Z do you need? What are you planning to cut and what is the largest depth cuts in what size materials?

On my Mechmate, I'm getting about 10" of Z with the 250mm slide, 7" main beams and the 6 roller Z slide. I could have got another 1-2" if I had gone to 8-9" mail beams or if I took out an extra layer of spoil board.

I guess the amount of Z really depends on a number of factors:
  • Length of cutter extending past the collet
  • Largest Z movement needed to cut the highest and lowest sections (such as using a 3" OAL end mill to cut a 2.5" hole in 5" material)
  • The quanity and size of the support/spoil board(s)
  • 4 or 6 roller spider
  • The type of shock and it's mounting bracket location on the slide tube
  • The height of the main support beams
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  #19  
Old Mon 09 June 2008, 22:07
orotemo
Just call me: orotemo
 
Warburg
Israel
First things first: didn't mean to annoy anybody, the word horrible was supposed to be written as "horrible", not as a truly horrible... - you get me .

David - thanks for the factors list. I'll tell you what I hope to achieve, and from your experience, please let me know what should I do.

I was hoping to get the 10'' (25mm) clearance under the cutting/molding tool. Once having a fully functional 3 axis MM, I would like to add an indexer above the table, at 5'' above the tabletop. I think of a dual purpose machine, one I can use to create molds in ply-wood and foam, and one that can take a plasma/oxyfuel head and cut pipes as well as sheets. by building such a sturdy - multi functional MM, I hope to reduce my economic risks - If I have a job in mold making - good, if not, the MM will join me in on plan B, cutting metal works.

I'll surely use 6 rollers for the spider plate, and additional tip will help.
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  #20  
Old Tue 10 June 2008, 00:16
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by orotemo View Post
I was hoping to get the 10'' (250mm) clearance under the cutting/molding tool.
With a cutter protruding say 3" [75mm] below the collet (typical for 3D work), and the collet being say 2 - 4" [50 - 100mm] below the tip of the z-slide, you will need about 140mm [5.5"] more height in the construction of the table and the length of the z-slide . . . . . . not good

Quote:
Originally Posted by orotemo View Post
Once having a fully functional 3 axis MM, I would like to add an indexer above the table, at 5'' above the tabletop. I think of a dual purpose machine, one I can use to create molds in ply-wood and foam, and one that can take a plasma/oxyfuel head and cut pipes as well as sheets. by building such a sturdy - multi functional MM, I hope to reduce my economic risks - If I have a job in mold making - good, if not, the MM will join me in on plan B, cutting metal works.
If you really want a multifunction machine, especially moving between plasma and routing, think of a table bed that is removable and height adjustable. Keep the x-rails fixed to the floor, but play with the table between the rails.
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  #21  
Old Tue 01 July 2008, 16:37
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
Send a message via Yahoo to Robert M Send a message via Skype™ to Robert M
Z-Slide travel dilemmas !

For those with the issue for the Z-slide travels distance vs gas spring availability vs total height clearances, here are some calculation & values to consider that I’ve came up with. ( Basically just another approach vs what Gerald explained in lower post #20 and the latest dilemma on gas spring selection !)

A - Router position vs bottom of Z-slide plate ( 10 40 334 ) :
If the router bottom part should be lower by +/– 1” ( 25mm ) See this

B- If one use the ELIMINATOR collet chuck on a typical Porter Cable 7518
It lowers by an additional +/- 2” ( 48mm ) from the router base.PC7518_Router-W_Eliminator_croped.jpg

If one intend to install a dust skirt/collector or a simple blast deflector, there is a maximum up ward position possible it can go and that is limited by the spider plate lower bearings set or the spider plated it self or the bottom of the tower carrier plates ( 10 30 455 ) witch ever comes first depending on your skirt/collector width and design. For this example, let stay the most upward limitation with a proper design skirt would be the lower bearings set, then it would be safe to say by my calculation you would end up with +/- 2.4” (61.6mm) higher then the top of you main beam ( 10 10 322 ) with out a cutter/end mill protruding one the Y-Car on the main rails!
Let’s call this one 0 collet height!

If one does not desire / wants to use the ELIMINATOR chuck and no dust skirt, add an extra +/- 1.5” ( 38mm) to this before you end up past the middle of the 2nd pair of Bearings (DualVee wheels) ! See this

Thus, with out the base board, the spoil board and a router end mill, you have some bases to calculate some Z-Travel variables.

To plot the available finish Z travel distance, one will have to calculate the main beams height selected (10 10 322) less the base board and maybe a spoil board combo (recommended) + the 0 collet height – less the protruding part of the end mill of your choice !

Let say the base board and spoil board combine thicknesses are : 2 x Ύ” = 1.5” (+/- 38mm)

Now calculate those variables together and you get the available Z travel distance

Ex : Main beam – bards combo + 0 collet height - router bit protruding the collet =
( ( 8” – 1.5” + 2.4” – 1.5” = (7.6” +/- 195mm) ). 7.6” or 9.1” travell with out the endmill plotted !

From there, one can select the needed gas spring stroke. But not all end here!!!
Other variables will need to be plotted in / adjusted in accordance with this strut (gas spring) selection.
IE : Gas spring Mounting bracket ( 10 40 372) height location ( a direct relation with gas spring total length ). The total length of the slide tube (10 40 364) and the slide plate ( 10 40 334)! Some carefulness will be needed here !

Not that I had nothing to do this after noon, “au contraire”, just hoping to help & contribute to this group with my view on this "sticky" point!
So Gerald, would you say I've done my home work OK ?
Amicalement, Robert
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  #22  
Old Tue 01 July 2008, 22:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Robert, you have certainly been doing some thinking. I used to think about these things over and over and then I came to some basic conclusions:

1. Promote the MechMate as an industrial board cutting machine - board thickness material, heavy duty cutting.

2. Let people know that they can extend the z-height but the penalty is then that the cutting becomes light duty.

3. That I will stay away from designing special z-slides because of all the complexities (as Robert illustrated above)
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  #23  
Old Tue 27 January 2009, 09:05
kanankeban
Just call me: Hector #89
 
Monterrey
Mexico
Quote:
Originally Posted by dmoore View Post
orotemo -

Maybe we should ask - how much Z do you need? What are you planning to cut and what is the largest depth cuts in what size materials?

On my Mechmate, I'm getting about 10" of Z with the 250mm slide, 7" main beams and the 6 roller Z slide. I could have got another 1-2" if I had gone to 8-9" mail beams or if I took out an extra layer of spoil board.

I guess the amount of Z really depends on a number of factors:
  • Length of cutter extending past the collet
  • Largest Z movement needed to cut the highest and lowest sections (such as using a 3" OAL end mill to cut a 2.5" hole in 5" material)
  • The quanity and size of the support/spoil board(s)
  • 4 or 6 roller spider
  • The type of shock and it's mounting bracket location on the slide tube
  • The height of the main support beams
I like your specs, Having 8" beams, should I go with the 250mm slide?
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  #24  
Old Tue 27 January 2009, 09:55
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hector, the real question is whether you will ever in the future want to cut foam blocks and then raise your x-beams beams from 8" to 12" . . . .

(For the last 5 machines we built, we asked ourselves the same question and decided that we don't need the 350mm slide ever - we built 250mm on all those machines)

However, there is no disadvantage of using a part of a 14" slide on a table with 8" beams - that part is the same stiffness as the 10" slide.
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  #25  
Old Thu 28 October 2010, 21:36
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Quick note on the 350mm Z slide
Typical 10/22 mm diameter gas shocks with 350mm stroke seem to have 795mm overall length.
This is longer than the backing tube for the Z slide, which is specced @ 665mm plus 50mm "slack".
I'm going to build a bracket to cater for the extra gas shock length. Time to start worrying about ceiling heights!

Last edited by Red_boards; Thu 28 October 2010 at 21:37.. Reason: fix typo
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  #26  
Old Mon 19 September 2011, 09:54
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
To rehash this subject, I have seen raising the top of the X beams but how would you low the table for a thicker spoil board for the "just incase" option and have extra room under the gantry? Add 2x4 sq tubes under the X beams?
The extra cleavance would be for a indexer.
Jas
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