Customizable strip feeder for SMD cut tape, version 1D

This is a fixture that holds a segment of "cut tape" with SMD components.

The design is done in OpenSCAD. It is highly configurable in the OpenSCAD customizer. The tape width and height can be adjusted, as well as the number of magnets on the bottom and their size.

A feature of this design is the small pin at one end. The pin fits in a sprocket hole of the cut tape, and thus makes sure that the tape does not slide up or down. It also makes the tape align consistently, so that when you reload the feeder with a new strip of tape, you do not need to re-align the component pick-up position.

The STL files in the “Files” section are for 16 mm and 24 mm wide tape. They use four 6 mm diameter, 1 mm thick magnets. As said, all dimensions are configurable, so you can use different magnets.

Hands-on experience

I have used various sizes of the strip feeders in our pick-&-place machine for a few weeks now, and to my satisfaction. The magnets keep the feeder in place (the pick-&-place machine has a steel build plate), and the pin in the sprocket hole makes sure the strip does not slide up and down.

Refilling an empty strip feeder works nicely, because you can slide each strip feeder out of the build plate, swap the empty strip of cut tape for a new strip, and slide the feeder back in its place. I remove the cover tape only after the strip feeder is in place, to minimize the risk that components jump out of their pockets due to possible shock and vibration.

The pin for the sprocket hole also results in good alignment of the components for pick-up. In the pick-&-place machine, strip feeders are defined as "trays", but with just a single row (or a single column, depending on how you arrange the strip feeders in the machine). You do not need to re-teach the pick-up position after refilling the strip feeder.

Update to version 1B

My (minor) gripe of the original design was that the length of the strip feeder was limited to the size of the 3D printer. In my case (Prusa MK3), this meant a maximum length of 245 mm. As I wrote above, for the pick-&-place machine, these feeders are like trays, and I put them along with the trays. Ideally, the strip feeders should therefore be equally long as a JEDEC tray.

Not having a large format printer yet, I added the option to print a strip feeder in separate sections. These sections are then glued together, to form a complete strip feeder.

Update to version 1C

After having swapped strips of cut tape in the feeders dozens of times without incident, in the past few weeks, I broke of the pins of two strip feeders within a few hours. These pins are definitely the weak spot, especially because they are printed vertically.

To amend this, I have added a variant where there is a hole, instead of a pin. You can then insert a small piece of steel wire in that hole. The wire must preferably have a diameter of 1.0 mm to 1.3 mm (sprocket holes in the cut tape have a diameter of 1.5 mm).

Update to version 1D

The design of the alignment pin was improved. It is now printed separately, flat. This means that it is much stronger. It also means that the pin now needs to be inserted in the strip feeder after printing, with a drop of glue.

It is still an option to create the strip-feeder with a round hole (instead of a pin).

Various other dimensions were optimized, partly to improve the ease of use, and partly to make the design more suitable for a 0.6 mm nozzle.

Rationale

There are many strip feeder designs already available. Some are elaborate, others are simple; some are commercial products, most are 3D printed freeware. And I have never used any of these, because I do not see the point. You will want to put tape on a tape feeder, so that you don't have to cut off another another strip of tape for the strip feeder every now and then.

I changed my mind when we had a project with many large and high components. Large components come in tape with widths of 16 mm, 24 mm or wider; the required step size may vary between 8 mm and 24 mm too. We can buy feeders for every combination of tape width and step size, but feeders are expensive, and you need those feeders only infrequently. And projects that use components of an uncommon size, it typically uses only a few of these on each PCB. The other criterion is component height: in our pick-&-place machine, components higher than roughly 6 mm run a risk of getting stuck in the tape feeder (this it is a limitation of our pick-&-place machine). 

These are the reasons why it makes sense to use strip feeders for components with special sizes. The reason to design my own, rather than use one of the existing designs, is that all other designs that I found, are for 8 mm and 12 mm tape. We need strip feeders for the larger sizes.

Printing, configuration & gluing notes

I have added STL files only for the strip feeders I have been needing myself so far. Over time, more will be added. However, the goal is that you create your own versions with the OpenSCAD source.

When printing in multiple sections, the sections will typically not be equally long. The OpenSCAD design places the cuts halfway between two magnets. So, changing the number of magnets affects the length of the sections. For example, if you use a Prusa Mini and you want to print a JEDEC-length strip feeder (322.6 mm), you will notice that printing it in two sections will not fit when using 5 magnets (one of the sections is still over 200 mm long), but reducing the magnet count to 4, evens the length of the sections out, and makes it fit on the Mini.

The purpose of the dove-tail fit is to align the sections while gluing. This is not a snap-lock construction: glue is needed. Glue is also needed for the magnets. I recommend epoxy glue.