In this video blog, John Weismantel, the Vice President of Engineering at Intec Automation, dives deep into the electronic circuit tester solution. Learn about how it works, its capabilities and why it is an excellent example of Intec's automation solutions.
My name is John Weismantel, I’m the Vice President of Engineering here at Intec Automation, and today we are going to be talking about the electronic circuit tester.
This machine is able to be run in a number of different modes and has a number of functionalities but, at the core it’s essentially testing the continuity, resistance values, and hi-pot testing of electronic circuits in large flexible or rigid panel arrays of circuits.
It will pull that into a predetermined position where we have four gantries in this piece of equipment. In one mode, it can be thought of as two machines in one, where you have redundant functionality on the left and right. In other modes, it can be thought of as additional throughput where you test some of the circuits in station one and then move forward and test the remaining circuits in station two.
The vacuum transport system is very unique. It is comprised of multiple blowers that deliver the negative pressure from up that blower, up into a honeycomb, aluminum panel. That aluminum panel has a number of holes through its topsheet as well as a very low friction coating, wrapped in a permeable polystyrene woven belt.
The belt allows a certain amount of flow to be pulled through that belt which is where you get the hold down force transferring up to the panel. But, it still allows the motion of the belt with respect to that vacuum table.
The low friction coating allows for both high hold down and very good repeatability in position. So any motion of that belt is a direct one to one motion of the panel. Most have a predefined position based on the recipe of that specific panel type.
Its long and thin tool that’s comprised of a number of spring loaded electronic test pins. Those test pins interact with the panel in certain areas that are specific test points on the circuit. When it’s pulled in, you will notice that the panel is read by a barcode reader to confirm that the panel type matches the recipe that was selected by the operator.
Once that is confirmed it will pull it the rest of the way in. The gantries all have two vision systems integrated into their mechanism that are configurable on 20 mm increment pitches. The machine is set up to be very modular.
The way that it's set up right now, is for a particular recipe. It has a particular end-of-arm tool put in place and the cameras are put into position very specific to that tool. The gantry will move to position those cameras over some regions of interest of the panel, and it will capture images of the fiducials that are built into that panel.
It will then provide offset distance values to the motion and will measure exactly where the test head or the end-of-arm tool needs to position itself in order to make electrical contact with all of the regions of interest in that panel that are important to run that test on.
The gantries are pretty unique in their mechanical design in the sense that they have the ability to articulate in a Y axis together by moving synchronously. They can rotate about a theta z axis by varying the Y1 and Y2 axis. They can move in the Z axis, all servo-driven. And, they can move in a small stroke, plus or minus a small distance, in the X axis.
So, the degrees of freedom that you have in each gantry gives it the ability to align the end-of-arm tool to the panel and how that panel is presented to the machine. If the operator were to set it slightly skewed by a few millimeters the gantry mechanism can detect that, measure that and automatically compensate for it and still put those pins exactly where they need to be within a very tight tolerance.
The system as a whole has 24 servo motors. Each gantry has five, backing conveyors are two, in-feed out-feed conveyors are two more. We are very proud of the motion systems that have been designed in this machine. It's a very robust and very accurate system.
We have the ability to measure and position and repeatability put those probes into a grouping that is in the single digit micron range. So, you can imagine that it gives you the ability to test circuits that have very small features of regions of interest.
It's a very versatile machine that can test a wide array of panel types and panel geometries and really be a modular tool for our end customer to run and expand as they develop different panel designs. This machine can grow with those designs and really test whatever they need to do going forward.
To talk about some really cool additional mechanisms that are built into the machine. You have a rack and pinning system which is made by a company called Nexen, and it's their RPS roller system.
This is a zero backlash mechanical interface. It's not like a traditional rack and pinning system that has an inherent amount of lash between the rack and the pinning gear. These are backlash free. They have a very high precision pitch on the rack itself. That contributes to our ability to position each gantry in very repeatable fashion.
Another aspect of the machine is something that we developed in-house at Intec. Initially we wanted to search and find a commercially available high-density connector that can be utilized for hi-pot testing. Hi-pot testing in this device can test up to 6,000 volts DC.
So, what we found was that the marketplace doesn't have a common product offering so we had to design a custom solution. The custom solution that we came up with is integrated into each test head. It’s a 64 pin density connector that has the ability to test up to 6,000 volts DC.
That gives our customers the ability to test a large number of circuits concurrently at the same time which results in a high throughput of equipment. You will notice the workmanship of not only the mechanical assemblies but the cabling and wiring throughout this machine.
Every cable is labeled at both ends, both termination points with a label that ties directly tied back to an electrical schematic. So, any servicing or diagnosis or debugging is very easy and quick.
You’ll notice that the wiring on the machine is such that each wire and the position of those wires in the bundles as they traverse from the device all the way back through energy chains and then down to eventually terminating into an electrical control panel is all very uniform.
It makes serviceability of the equipment in the future, if you ever need to replace a cable or diagnose a potential cable problem, it makes it very easy to do that.