Create two part mould for spheres

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jbbjshlws
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Create two part mould for spheres

Post by jbbjshlws »

Hello,
I am trying to create a two part mould for spheres that i can turn into ice, I feel i have pretty much made it, but I am finding that the modelling shape profile is not working as expected, I get a weird edging instead of a clean edge against the material.
The end goal is symmetrical ice spheres, As you can see in the attachment I am getting some weird outline as it ramps into the material. I have added the model settings also. Please advise

Cheers,
Jbb
Attachments
2017_10_29_22_06_07_Aspire_Ice_Tray_v2_3D.png
2017_10_29_22_06_07_Aspire_Ice_Tray_v2_3D_settings.png

LittleGreyMan
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Re: Create two part mould for spheres

Post by LittleGreyMan »

I would not use a 3D component for this but simply use a drilling toolpath with a tool of the right diameter.

Even if it is a specific tool, it will probably cost way less than machining this in 3D.


Of course, if it's not a commercial use, that's another story. In this case, a moulding too lpath is probably the way to go.

HTH
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garylmast
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Re: Create two part mould for spheres

Post by garylmast »

Here's the tutorial for creating a dish.

http://support.vectric.com/tutorials/V9 ... ideo_id=64

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Rcnewcomb
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Re: Create two part mould for spheres

Post by Rcnewcomb »

I get a weird edging instead of a clean edge against the material.
Add a zero plane of you haven't already.
Model/Create Component/Add Zero Plane
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Leo
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Re: Create two part mould for spheres

Post by Leo »

I did a test on "spherical" shape recently. I successfully made a spherical shape. I am very much aware of the toolpath that you get as the shape gets more and more vertical.

The whole issue is with stepover. The stepover is always in terms of the "horizontal" distance of X or Y, and never in terms if Z. As the sides of the sphere get more and more vertical the horizontal stepover starts to convert to a very large vertical stepover component.

Someday, I will do the math on the vertical component of the horizontal stepover component. It just a little trig but the angle changes at every horizontal stepover.

My sample was on a 10 degree wedge. I created a 3D toolpath for the spherical outer edge of the wedge, but I set the toolpath to .0003 That is NOT a mistake in decimal points - I set the stepover to 3 ten thousanths of an inch. That gave me a smaller vertical component and the spherical radius worked.

I am guessing that if you broke the semi sphere toolpath, by drawing circles, into 3 areas you could create toolpath with varied stepover. The most vertical area would be a stupid small stepover like .0005 - .0003, the middle area where the average angle of the side is - er maybe 40-30 degrees with a stepover of - say about .0008 to .001, and the bottom area will be somewhat normal at .003-.005

Post all three toolpaths together into one file.
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highpockets
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Re: Create two part mould for spheres

Post by highpockets »

I haven't tried cutting it, but the preview looks OK.
Image 041.png
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jbbjshlws
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Re: Create two part mould for spheres

Post by jbbjshlws »

LittleGreyMan wrote:I would not use a 3D component for this but simply use a drilling toolpath with a tool of the right diameter. a moulding too lpath is probably the way to go.

HTH
Non commercial, Ooak project with I need very specifically 0.68" spheres, using a 3.175mm ball nose endmill
The test you ran Highpockets, what were the dimensions of the spheres? would you mind sharing the file or settings?

Leo, I tried with a really small stepover, it still has the ragged edging, to a lesser degree but not like the LittleGreyMan's example

Garylmast: The issue only seems apparent as you get closer to the 90 degree with the shape, shallow items do not face the issue, thanks for the link though!

Rcnewcomb:
Add a zero plane of you haven't already.
Model/Create Component/Add Zero Plane

I have added the zero plane, good news is the edging looks fine, bad news is this now add's 6.5 hours to the job... anyway around this?

Cheers, Jbb

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Mike-S
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Re: Create two part mould for spheres

Post by Mike-S »

I have added the zero plane, good news is the edging looks fine, bad news is this now add's 6.5 hours to the job... anyway around this?
Does your tool path cover only the spheres, or is the whole surface being machined?

jbbjshlws
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Re: Create two part mould for spheres

Post by jbbjshlws »

Mike-S wrote:
I have added the zero plane, good news is the edging looks fine, bad news is this now add's 6.5 hours to the job... anyway around this?
Does your tool path cover only the spheres, or is the whole surface being machined?
Only the spheres

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highpockets
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Re: Create two part mould for spheres

Post by highpockets »

jbb,

I didn't save the test, but I just redrew a sample with component and molding toolpath time for roughing toolpath 5:19 minutes on my machine and 2:43 for molding toolpath.

I'd be happy to share the file, but even zipped it's over the 2mb limit. If you PM me your email address I'll email it to you.
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jbbjshlws
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Re: Create two part mould for spheres

Post by jbbjshlws »

highpockets wrote:jbb,

I didn't save the test, but I just redrew a sample with component and molding toolpath time for roughing toolpath 5:19 minutes on my machine and 2:43 for molding toolpath.

I'd be happy to share the file, but even zipped it's over the 2mb limit. If you PM me your email address I'll email it to you.
I tried to pm you but under your profile contact section there is no button or text box to do this :-(

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highpockets
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Re: Create two part mould for spheres

Post by highpockets »

jbbjshlws wrote:
highpockets wrote:jbb,

I didn't save the test, but I just redrew a sample with component and molding toolpath time for roughing toolpath 5:19 minutes on my machine and 2:43 for molding toolpath.

I'd be happy to share the file, but even zipped it's over the 2mb limit. If you PM me your email address I'll email it to you.
I tried to pm you but under your profile contact section there is no button or text box to do this :-(
Had not noticed, you don't have enough posts to have PM capability.

Post your email address, if you don't mind.
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jbbjshlws
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Re: Create two part mould for spheres

Post by jbbjshlws »

haha no worries,
jbbjshlws at hotmail dot com

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highpockets
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Re: Create two part mould for spheres

Post by highpockets »

OK, just sent you an email.
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jbbjshlws
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Re: Create two part mould for spheres

Post by jbbjshlws »

highpockets wrote:OK, just sent you an email.
Ok, it is 100% the Zero Plane that is fixing up the edging. How are you managing to have only the pockets cut out and not the Zero Plane?

Cheers,
Jbb

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