Mike, help!
I built your cool SMT fixture, but I don't have a 3D printer, and the rubber clamp tip doesn't work at all for 805 parts.
What do you suggest I use instead to secure the SMT parts to the fixture?
Thanks,
Josh
Keep the large rubber tip, you'll need it for larger SMD components like power inductors or large chip caps. On the other bolt end add a tapered plastic tip, just about anything will work. You could get a plastic or wooden rod/dowel and turn down the tip, then drill and tap the other side for the bolt. However you do this, don't engage the bolt too deep into the tip as it distorts the fields more than the plastic tip.
Edit: The nylon screw/bolt is a good idea as you can easily taper the end to a dull point. Also did you add a internal shield within the box? This is worthwhile if you didn't.
Experiment with the Plunger base height above the PCB, we found ~10mm works with the Tip & Plunger fixture we have (there are a few types), and most of the SMD stuff we work with. You can fine tune the height with the bolt adjustment for different similar physical size SMD components.
When you use the fixture don't use too much force, often just a light pressure from the tip is enough. Get yourself some precision (0.5% if possible) 1, 5, 10, 15, 20, 30, 40, 50 and 100 milli-Ω 2512 resistors, start off with these larger SMD components and study the profile of the SMD components, some of the SMD resistors have the contact area recessed and often they make better contact flipped over face down.
We've found the larger more expensive quality SMD components seem to be easier to work with, altho we've tested some 0603 and 0805 components with patience.
Make sure the SMD and Fixture surface area is clean, we often clean with IPA and a cotton swab. Play around with how to engage the contacts (Hc, Hp, Lp, Lc) on the two SDM end conductive surfaces. Sometimes you'll get ridiculous readings, either way too high, low or negative, this is due to not having all 4 contacts engaged.
Don't forget to make a good Zero Ohm Shunt, critical for quality low Z measurements.
Best,