Need A Starbucks cup top in mini

[Radioman1017]

Hey all,

I'm still working on learning modelling but my wife (who bought me my printer) is pressuring me for a piece for her earring business.

I need the top of this cup:

http://thedisneyblog.com/wp-content/upl ... -cup-2.jpg

The wide end should be 13mm. Hollow if possible. These are the pieces she makes.

https://www.etsy.com/listing/194278404/ ... ome_feat_1

She has the cups but cannot get lids any longer so she wants me to try and print some for her.

If anyone could do this for me, I'd be most appreciative. I'll send you a nice pair of Starbucks earrings for you or significant other.

Mark

[RetireeJay]

IMHO, that's an extreme challenge for 3D printing!

- The dome at the top becomes almost horizontal, which 3D printers can't do without support.

- It needs to be clear or nearly clear, and pretty smooth, meaning single-wall thickness. That's not very compatible with support (unless you are using two materials and wash one of them away).

- 3D printing is fine for one-offs or quantities up into the tens, but if you are thinking of going to hundreds or thousands of pieces, then the overall cost and effort to maintain and feed the printer(s) is going to become burdensome. The original Printrbots used printed plastic parts, but they switched to wood and then metal for efficiency of manufacture in the quantities needed.

It would be easier to print a form for the top, and then have some way of creating the tops using the form by pulling heated plastic film over the form.

[wd5gnr]

That's going to be tough to print hollow without support. And it isn't going to be clear. If all you want is a 13mm sphere cut in the middle with maybe a small brim around it, that's easy enough to do in OpenSCAD (shameless plug: http://www.amazon.com/OpenSCAD-3D-Print ... 1500582476) and I can send you an STL done like that. It would be easy enough to model it hollow too, but hard to print. So...

Code: Select all

$fn=32;

// Lid -- Williams
lid_dia=13;  // diameter
rim_dia=14.5;  // rim diameter
rim_hi=.75;  // height of rim
hollow=0.95;   // 0=solid .95 = 95% hollow (etc.)
hole_dia=2;  // diameter of hole in center (0 for no hole)
hole_depth=4;  // depth to cut hole (big number ok for hollow)



lidr=lid_dia/2;

union() {
// make rim
   difference() {
    cylinder(r=rim_dia/2,h=rim_hi);
     translate([0,0,-.05]) cylinder(r=lid_dia/2,h=rim_h1+.1);
}
// main part
  difference() {
   sphere(r=lid_dia/2,center=true); // dome
// cut off half
   translate([0,0,-lid_dia*2/2]) cube([lid_dia*2,lid_dia*2,lid_dia*2-.05],center=true);
// if hollow, cut out the inner part
if (hollow!=0)
   sphere(r=hollow*lid_dia/2,center=true);
// if hole desired, cut it out
if (hole_dia!=0) {
   translate([0,0,lid_dia/2-hole_depth]) cylinder(r=hole_dia/2,hole_depth+.1);
   }

}
}


If the STLs aren't what you want, just go edit the OpenSCAD at the top to suit you. Go get OpenSCAD and load the text in there. Press F5 to see what it will look like. Press F6 when you are happy and then use File | Export to save as an STL. Don't forget the F6 FIRST!

[evanalmighty]

You can probably make the top flat and print it upside down.

[thawkins]

This is more a job for vacuum forming you can buy sheets of clear plastic suitable for molding, and building a vacuum forming frame is easy. A domestic vacuum cleaner can provide suffient suction to pull the plastic onto the mold. Use either an oven or a heatgun to soften the plastic until it can be molded

http://hackaday.com/2014/10/19/diy-vacu ... the-cheap/

http://www.widgetworksunlimited.com/The ... s_s/36.htm

http://makezine.com/projects/making-a-d ... n-one-day/

[orangefurball]

I had two large jobs so far, one of 225 pieces and one of 125 pieces. When you print you have to make sure the items are very easy to print or else you can't do anything close to mass production (without a larger printer)

If you can somehow get the sphere to print with a single layer, you can use T-Glase clear and cost it in Smooth-on's new 3D print coating stuff.

The process is outlined here, however I agree with THawkins that vacuum forming would be a better way to do it.

[Radioman1017]

Thanks for the replies, all. A couple of notes.

We're not looking for mass production, really. She sells maybe 20 a month. We're just trying to replace a piece she can no longer find.

As for vacu-forming, I totally agree. It's been on my to-do list to build one for a long time. Maybe this will be the push I need.

A buddy of mine at work modeled one up for me but I can't get it to print. Not sure why. Does anyone have time to look at this?

https://www.dropbox.com/s/id7dvephrcvlt ... p.stl?dl=0

I realize I'm probably asking for the impossible (due to supports and the like) but I'm just trying to exhaust all of my options before telling the wife I can't do it.

Thanks!

mark

[RetireeJay]

Your buddy doesn't even understand the basics of 3D printer orientation. The only sane way to even attempt to print this would be with the large-diameter open circle in the X-Y plane, with the dome building up in the Z direction. Depending on the material you are using, the layer thickness, the trace width, and the use of fans, etc, the steepest "overhang" angle you can expect to do is between 45 and 60 degrees. Beyond that point, you're just dropping threads into the air. And printing this single-wall object with support (made of the same material on a single-printhead printer) is going to create a very messy object that will probably break before you can get it separated from the support.

I had a few minutes of spare time [Retired...] so I re-oriented your model in Netfabb and gave it a try. As I predicted, the overhang failed at about the 45 degree angle. I note that your model is only about 0.2mm thick. My nozzle (and therefore my minimum trace width) is 0.4mm, so the end product may have the right shape but there's no guarantee that it would fit on your doll-sized cup. In fact, achieving that precision is going to be difficult!

CoffeeCupLid-DiagonalView.jpg

CoffeeCupLid-TopView.jpg

CoffeeCupLid-SideView.jpg

[Radioman1017]

Jay,

Thanks for your time. My friend is a brilliant modeler (we work for a large video game studio) so he did his best.

I suspected the size might be an issue on this piece and I wondered about support. I'll let the wife know this won't work.

Thanks all!

Mark

[RetireeJay]

My friend is a brilliant modeler (we work for a large video game studio) so he did his best.

I'm sorry if I seemed to insult your friend's ability. Since I do virtually all my own CAD design for things I make, I'm very highly attuned to the specific requirements of designing parts for 3D printing. I, too, have a brilliant Mechanical Engineering friend whose CAD abilities vastly exceed mine; but when he asked me to make a part for him, we had to go around the loop several times before we could get his part oriented and cut correctly for 3D printing. So your experience with your friend is quite normal.