Peter Reinhardt, President, REINHARDT System- und Messelectronic GmbH
Selecting an in-circuit tester depends on the quantities and on the variety of the loaded electronic boards. Almost 90% of all the American systems and about 50% of the European systems are developed for testing 100,000 units and more. In this case, the very high investment of this group of test systems, the fixture cost, the programming cost and the support cost are split in proportion to the quantity which may be acceptable.
The European market and especially the German market operate on different figures. A good 75% of all electronic producers have a variety between 50 and 500 different types of PCBs at production lots between 50 and 400 units each. Production levels greater than 5,000 units are rare. Take the initial capital investment, the programming, the fixturing and the support cost of the systems mentioned above and your tested PCB cannot be sold at a profit.
If your company belongs to the group with high variety and low quantity, your selection must be totally different. Different variety will demand different priorities to look at. If you have only a few types with medium-size lots, i.e. 1,000 units or more of a production lot, programming and fixturing is not a a major cost factor. In this case, investment is the most important factor. If you have a big variety with typical production quantities of 50 to 400, your initial investment is of secondary importance to fixturing and programming costs. This means that we have systems on the market now, which require only a tenth of the typical cost for fixturing and a tenth of the typical cost and time for programming. In this case low-cost programming and fixturing is the most important point in your decision.
Surprisingly, the systems which are designed to accommodate production volumes of 100,000 units of one type and more, are not faster, not more accurate and not more reliable than systems in a lower price range (between 20,000 and 80,000 Euros). For this reason the more expensive systems are basically obsolete and have absolutely no future. They are very time-consuming and cost-consuming in the production of fixturing and also require highly-trained personnel for programming.
You should select a system which is modern, in most cases relatively inexpensive and designed for easy programming. The selected system should also include a lot of automatic tools for most of the repetitive tasks. It is very valuable if you choose a system that can be programmed automatically by software-tools such as FABMASTER
(TM) and other similar tools. These kinds of software modules are very pricey and require a high level of training. If you choose a test system like
REINHARDT ATS-KMFT 670, you get a solution with typical fixturing cost between 300 and 600 Euros and programming cost of 100 to 300 Euros. The training requires 7 hours and the operation closely follows the WINDOWS-philosophy by filling in only the test points and parameters. Automatic generation is also available and auto-programming with
auto-guarding and auto-debug is part of the software.
You should be aware of the difference between an In-circuit Tester and a
Manufacturing Defect Analyzer (MDA). An In-circuit Tester uses backdriving for digital components while an MDA uses only the input/output diode test and the short circuit test for digital components. The backdriving is very costly in hardware, fixturing and programming. The backdriving test was possible 30 years ago for 70% of the digital components, today it is difficult to apply this to even 20% of the components because of new technologies and added complexities of the devices under test. The results of the MDA-testing have the same fault coverage as an in-circuit tester with backdriving. All the components we use can be tested today by most of the test systems - with very few exceptions. The high-voltage test of varistors, zinc-oxide type or gas discharge, are still very limited, but there is very little limitation for the rest.
It is very important that your test system can produce test results for statistics, can do networking with servers and can also print out test reports. Decentralized repair and programming stations should be available. Service and calibration of the system is an absolute must in our days. Service contracts for software and support should be payable, i.e. in a price range of less than 3% of the investment per year. A hotline should be available directly to the test system designers - not simply to support personnel who are only marginally familiar with the system.
Since we found that more than 75% of all vendors of electronic PCBs have high varieties and low quantities of production, the price of the test system should not exceed 80,000 Euros. The fixturing cost and the programming cost together should not exceed 800 to 1,000 Euros. Additionally, the test system should be well supported in repair and calibration and should be serviced for at least 15 years.
If you chose a system now which also has easy programming and is very flexible to the open world, you will definitely make the right decision, as this decision will also be appropriate for production lots of more than 100,000 units.