Need an Idea for a Jig

[Tim Bateson]

I've been doing these very small anodized parts, a few dozen here and there. Now they are coming by the hundreds and I'm at a loss at making a good jig. I could use some ideas. Aligning by hand is slow and getting tedious.

Top size: 1.14 inch x .33 inch. The bottoms are flat, smaller than the top, but irregular shaped. I actually have 4 different shapes and sizes, but all somewhat similar.

I know a picture would be helpful, but the customer has requested I not yet post any - sorry.

[Samuel Espy]

Tim, I understand that you can't post a picture, but I do not have a sufficient grasp on the geometry of the part. Maybe I can help by trying to advance the description of its geometry. Please don't think my descriptions are intended to be condescending. If anyone is going to offer decent suggestions, we need to describe the 3D geometrical shapes w/o the use of images and that is not trivial. Let's start by making an analogy between your 4 shapes and 4 coins lying on a flat surface. Please read my assumptions and conclusions carefully and tell us which are correct and correct those that are not in order to improve all of our understanding of the geometry of your items.

I assume by 4 shapes you mean there are 4 different cross sectional shapes. For a coin the cross sectional shape is a simple circle so in our coin analogy there might be a penny, nickle, dime and a quarter. In addition to the cross section being more complex than a circle, you indicate that the bottom of your part is smaller than the top. (I assume you need to engrave the top BTW.) Would a correct analogy a coin in which the top circle of the coin is larger than the bottom? Also is the cross sectional shape of the top the same cross sectional shape as the bottom only scaled larger for your parts? Is the top surface parallel to the bottom surface as is the case for a coin?

Here is a stab in the dark suggestion assuming 1) the top is to be engraved and 2) the top is a planar or flat surface (and probably lots of other poor assumptions). Under these (likely incorrect assumptions), why not use a dimensionaly-stable jig material like MDF, engrave holes in it that are the size/shape of the top cross section of the part but make sure the holes are small enough to require a gentle press fit of the part into the holes. Obviously a different cross section will be used for the 4 different types. Place the jig onto the laser bed or something else very flat and rigid. Press the parts into the holes with the top of the part face down (i.e. into the hole first) and press the part all the way in so the top surface of the part is flush with the bottom of the jig until the top surface of the part is residing against the laser bed/flat surface. Turn the entire jig over resulting in all the top surfaces of the parts being up now and in a plane. Then engrave. I am sure I am simplifying due to misunderstanding geometry and thus this approach is not possible for some reason, but maybe there is sufficient description for you to leverage when improving our understanding of the geometry. Best of luck.

[Gary Hair]

Scan the bottom, import into Corel and trace. make a fixture out of thin acrylic or rowmark and use trophy tape to attach it to some 3/4" mdf. Attach to the mdf before you cut it then you know it's aligned perfectly when you engrave. That's exactly what I did for a job of mine that sounds very similar. I have about 30 different parts that are all different sizes and shapes. With the exception of three of them the top and bottom are parallel.

[Tim Bateson]

Thanks guys. Both of these are great ideas. I'm going to do a quick mock-up of both today & see which works best.

[Keith Winter]

Hi Tim,

I saw that the customer asked you not to post the part so it's hard to say 100% but I'll give it a shot.

Cut the shapes out of mdf, if the shapes are really complex, a rectangle that's the exact width and height of the product will do quite well also. Repeat pattern every 1/2 and you're done. If there are additional details you can provide please post and I'll do my best to help. We make a lot of jigs, it's really just getting an idea for the product at hand to determine the proper jig.

[Ruben Salcedo]

You have received very good tips from others here, i just wanted to add another type of material to use, is cheap easy and fast to cut, I use corrugated Pads from Uline they are inexpensive but also you can just cut it from a box if all you need is one up jig, I have many that I have created and they have last more than I thought, for dimensional jigs you just cut several sheets and glue them with wood glue it set very fast, here a sample of one I did to engrave bottle openers.

[Mike DeRegnaucourt]

Hi Tim,

Here's the basic idea of how I would make the jig myself. For simplicity sake, I just used a pentagon shape but the concept is the same for whatever shape your items are. I hope my quick-n-dirty mock-up, using MS Paint...lol...since I do not have access to CorelDraw at the moment, makes sense.

Jig.gif

[Scott Shepherd]

Early on, I used to try and make exact shapes for odd shaped pieces to fit into. At some point, the lightbulb finally came on and I realized that the vast majority of things just needed basic shapes cut out. I think someone mentioned it earlier in this thread. In the case of the pentagon Mike posted, I'd just cut a square. If orientation was critical, I'd put a couple bumps in the shape so that it only fits one way.

If I look at all my earlier fixtures, they are all custom shapes. Now I look at my recent fixtures and the are almost all very basic, simple shapes, even though they might be holding complex shaped parts.

Just something to think about. There's really no reason it has to make the blank shape. It just needs to hold it in place to engrave it.

[Tim Bateson]

I did get this last job completed. Used scrap material I had on-hand - 1/8 ply. Took the common features of all of them and made 1 jig to fit all of the shapes. Needs tweaking, but saved me major time.

Sorry again about the lack of details and photos. Sometimes we all have to deal with confidentiality agreements. I think they are awaiting patents.

[Kev Williams]

I use USPS priority mail boxes for jigs. USED ones of course Dog tags, parts trays, watches...

The cardboard is thin and rigid. Parts are easy in/out. Little bits of 2-sided tape keeps it flat and in place. Cut the pattern from the job, place the parts, run the job. Engraving will be dead on.