The 3D printed golf ball stencil: how Ball Buddy is made in laser-sintered nylon

What is SLS 3D printing?

Most people picture 3D printing as a hot nozzle squeezing out plastic like a very small icing bag. That's filament printing, and it's brilliant for prototypes. SLS is a different animal. The printer holds a bed of fine nylon powder. A laser scans across it and fuses — sinters — the powder exactly where the part is, then the bed drops by a fraction of a millimetre, a fresh layer of powder is spread over the top, and the laser draws the next slice.

Do that a few hundred times and a solid part is sitting inside a block of loose powder, like a fossil in sand. Because the unfused powder holds everything up, there are no supports to snap off and no marks where they were. Overhangs, tunnels, the curved shell that hugs the ball — the laser just draws them.

What is a Ball Buddy made of?

PA12 nylon. It's the material laser-sintering was built around, and it's a good one for something that lives in a golf bag: tough enough to be thrown in with the clubs, flexible enough to clip over a ball a thousand times without fatiguing, and light. It doesn't absorb much water, so it doesn't swell or warp in the boot on a wet Saturday. The finish is a warm grey with a faint sandy texture — pleasant to hold, and it doesn't skid on a wet ball the way glossy plastic does.

The same family of nylon is used for working parts in cars, in medical devices and in eyewear — places where a part has to do a job for years rather than look good for a week. We could have chosen something cheaper. We chose the one that will still be in your bag next season.

Why not print it on a home printer?

You could — there are files on the internet — and if you own a printer it's a fun evening. But a golf ball stencil asks for three things that desktop printing struggles with:

• Tight slots. Every line, dot and letter is a 2.4 mm slot with a bevelled lead-in at the mouth so the pen finds it. In filament, that bevel comes out as steps and the slot walls carry ridges that catch the nib. Sintered nylon comes out smooth and true to within about a third of a millimetre.
• Thin, springy walls. The shell that grips the ball is 2 mm of nylon with a gentle spring in it. Filament parts are weak between layers — exactly where a clip-on shell flexes — so they crack along a layer line after a few weeks. A sintered part is the same strength in every direction.
• Heat. PLA starts to soften around 60 °C. A car parcel shelf in July gets there. Nylon shrugs it off.

Resin printers get the detail right but the parts are brittle and yellow in sunlight — the wrong material for something that gets dropped on a cart path. So: nylon, sintered. Not because it's fashionable, because it's the one that works.

How your design becomes a part

1. You design it. Lines, dots, arrows, your initials, on the ball, in the golf ball stencil designer. The 3-D view shows the exact part that will be printed — not an artist's impression. (Wondering what the marks already on your ball mean? That's covered here.)
2. The design is checked for printability. While you drag things about, software checks every wall is at least 1 mm thick, every opening at least 1.2 mm wide, and every letter's middle is held by a tab you could print. If it isn't, it tells you before you pay. Nothing gets to the printer that can't be printed.
3. Your marks are cut into the master. The Ball Buddy shape — the clip, the finger slots, the ball socket — is one master file that's been test-printed and drawn through. Your design is cut through its shell and the result is your file, watertight and unique.
4. It's nested into a build. Every few days the waiting orders are arranged together in the printer's volume, the way a tailor lays out pattern pieces on cloth, and printed overnight.
5. Cool, dig out, clean, check. The build cools slowly so nothing warps. Parts are lifted out of the powder, blasted clean, and each one is clipped onto a ball and drawn through with the pen it was designed for. Then it's boxed and posted, Royal Mail Tracked.

Can I download the STL and print it myself?

Not from us — the printed part is what we sell, and a filament copy of it wouldn't be the thing we're happy to put our name on. If you already run a laser-sintering machine you know why. If you've got a desktop printer and want to experiment, the files people share for "golf ball stencil 3D print" will show you the idea; when you want one that holds the ball without you gripping both, draws clean through a proper lead-in and survives the bag, that's the one we make.

Prefer a design that's already done? The ready-made golf ball stencils are printed exactly the same way, to order, in the pen colour you choose. Weighing up an ink stamp instead? Our golf ball stamp vs stencil comparison is honest about where each one wins.

How long does a 3D printed nylon stencil last?

Seasons. There's nothing to wear out: no hinge, no battery, no coating. Ink that builds up around the slots wipes off with a drop of rubbing alcohol on a cloth. The texture might polish a little where your thumb sits. If one ever does break — it hasn't happened yet, but nothing's immortal — email us a photo and we print another from your design, which is kept on file for exactly that reason.

Is 3D printing wasteful?

This kind isn't, much. Nothing is made until someone orders it, so there's no stock sitting in boxes and nothing unsold to throw away. Most of the powder the laser doesn't touch is sieved and goes back into the next build. There are no supports to snap off and bin. And a part that lasts for years is the least wasteful kind of part there is.

Questions people ask