Issue link: https://iconnect007.uberflip.com/i/472660
March 2015 • SMT Magazine 75 hOW TO SELEcT an aUTOmaTIc PIck-anD-PLacE machInE continues sMt quICk-tIPs the need to teach the vision system how to identify part images that are stored in the machine's database; a slower method of centering due to time slice required for processing; vision is more costly than the mechanical method; for look-down vision, the part may move from its pickup point to its placement on the board • Size range: 0402 to 15 mm The look-up vision method is the most ac- curate centering method available. The compo- nent is first picked up from the pick-up area, moved to a camera station that looks at the bot- tom of the component, and calculates its center position. • Pros: True touchless centering, handles delicate components; accurate down to +/- .001" positioning capability • Cons: Typically, a longer setup time due to the need to teach the vision system how to identify the image that is stored in the machine's database; a slower method of centering due to processing time; Vision is more costly than the mechanical method • Size range: 01005 to 50 mm (can see smaller and more detail) The pick-up and centering method you choose will have a great deal of influence on the quality and speed of your production needs, along with how to relate this accuracy back to the machine. But that's just the beginning. In the next column, we'll continue our next chap- ter on pick-and-place machines by reviewing: 1. Mechanical positioning methods 2. Feeders (number, type, etc.) 3. Encoders (rotary vs. linear) 4. Software vendor Support When evaluating any type of SMT machine, consider factory support as one of the most im- portant assets of your purchase. The best way to learn how a company treats its customers is by word of mouth. Talk to several customers to find out how happy they are with the machine, the seller, and the support they provide. Where is the manufacturing plant? Can they help trou- bleshoot alignment issues over the phone? Do they offer field service? Do they have spare parts in stock for immediate shipment? While there isn't much of a used market for manual, ma- chine-assisted or enhanced manual pick-and- place machines, it's still a good idea to ask your supplier about their older machines in the field, and if down the road, spare parts are available, and about their capability to customize a spare part if the machine becomes obsolete. Ask what the expected life-cycle of the product is. The in- dustry standard is seven years. Remember, there is a difference between a true manufacturer and an equipment supplier or distributor. SmT robert voigt is vP of global sales at ddM novastar Inc. he may be reached at rvoigt@ddmnovastar.com.