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A turnkey line can simplify purchasing, machine compatability and service.

Many companies spend thousands of dollars each year simply to determine general strategic directions for SMT production equipment requirements. Large companies typically identify individuals, or groups of individuals, who are responsible for charting the future course within the company. Representatives from engineering, manufacturing and operations, and design spend long, intensive sessions discussing equipment requirements for the next few years.

What they are attempting to determine, of course, is one single solution for the company's production needs. The fact that this process has been going on essentially without change for the past 20 years within the American manufacturing industry is evidence of how important this is held to be.

A number of people have an influence over the purchase of an expensive turnkey SMT system. Generally, unless it is an addition to an existing pool or a replacement for an older piece of SMT equipment, it must also pass the selection committee's requirements and get approvals from the head of the production department from whose budget it will ultimately come and, often, the president of the company. This is not an easy task.

The price tag alone makes an SMT line a major purchase. The decision takes on even greater importance, however, because it in part determines the long-term strategic direction of the company.

Once the decision is made to purchase equipment, it must be determined whether to purchase it piecemeal or from a single supplier. The difference between turnkey SMT vendors and single-product suppliers is generally this: Single-source vendors provide useful solutions to a specific area of SMT production, whereas turnkey vendors' expertise extends to the entire production line.

What's easier? Placing a single purchase order with a single vendor? Or numerous POs with numerous vendors? Obviously, the former is a great advantage, provided a company can find a vendor with all the equipment that corresponds to its needs. This approach is less time-consuming and all questions can be answered with one phone call or visit to the vendor's demonstration site.

Here we look at the single-source purchase. Keep in mind that this approach may not work for everyone; it depends on a company's specific needs.

Seven basic items should be considered when purchasing an SMT line:

1. How flexible does the production equipment need to be?

• Low to medium volume?

• High volume?

• Medium to high product changeover?

• Should it be a dedicated manufacturing line?

2. Consolidate efforts. The lean staffs typical of today's assemblers make it difficult to allocate time to research various equipment. When purchasing from one source, consider consolidating efforts. Suppliers of full lines of equipment will have application engineers or sales engineers who can help with requirements. They will review equipment requirements based on the production numbers. They can provide recommendations on:

• Stencil printers. Based on the production numbers and available manpower, the applications engineer will verify production numbers in support of a batch or inline printer.

• Pick-and-place throughput calculation and line balancing. When comparing multiple vendors' equipment for throughput, make sure all quotes are based on the same PCB assembly (or predefined PCB such as an IPC board).

• Reflow ovens. Verify or determine what size oven is required. The size of an oven is not as important as the throughput requirements. The throughput of an oven is based on the solder paste manufacturer's "time" in a heated chamber, not the throughput of a pick-and-place system. Solder paste needs a specific amount of time at a specific temperature to perform properly. Pick-and-place is typically the bottleneck.

These items will provide the customer with throughput utilization and line balancing to eliminate or reduce time process conflicts.

3. Determine whether the line will be inline or batch setup.

• Not all SMT vendors offer both batch and inline systems.

• Turnkey suppliers can provide a complete selection of line loaders, inspection conveyors, buffering units such as LIFO or FIFO, line gates and line unloaders. The turnkey supplier will install these items at the same time as the other equipment. Note: Most suppliers offer private-label conveyors.

4. Another consideration is the upgradeability or growth path of the equipment selected.

• Can equipment options be upgraded in the future?

• Is the operating software upgradeable or has it been "locked" (i.e., no more work being performed on it)?

• Equipment outgrown? For example, if the current pick-and-place system is semiautomatic and there is a need for fully automatic, can the outdated equipment be traded for the latest version?

• Is the software offered on each model (semiautomatic and automatic) compatible or identical? If yes, it will greatly reduce the need to retrain personnel. This is a significant time-saver.

5. Once a PO is placed, the next step is to coordinate the various utilities requirements. Whether one piece of equipment or several, it is the responsibility of the customer to ensure the electrical, compressed air, vacuum, and ventilation and exhaust is completed before the equipment arrives. Once the utilities are ready, notify the vendor's service manager, who will coordinate the installation of all the purchased equipment, plus onsite training. Note: Exhaust is particularly important with ovens; too much or too little can affect the oven's performance.

6. Internal coordination of services. At the vendor's site, there is a measured amount of work to ensure that the equipment is built to the highest quality standards possible. In addition to a standard vendor PCB test for the pick-and-pace system, in some cases the customer's specific PCB assembly is programmed on the entire line. The entire line is not necessarily set up inline but instead passed to each piece of the customer's equipment to ensure that it is ready to go into production once the system has been installed. Also, this process verifies the throughput rate. This is particularly important if the PCB assembly is large or if the equipment is at the edge of its capability.

7. One phone call. If an issue arises after the equipment has been installed and is running, and personnel have been trained properly, a single phone call can be all it takes to resolve an issue or to schedule a site visit. The issue could be a programming question, process or support issue. This could be the pick-and-place, printer, reflow oven, a conveyor or a communication issue between the systems. With one phone call, you can get an answer. Most, if not all, single-source SMT equipment manufacturers have a product specialist or a group of specialists on hand who are system and process experts responsible for customer support. This eliminates one vendor pointing a finger at another; e.g., solder paste manufacturer vs. printer manufacturer vs. oven manufacturer.

• The equipment vendor and customer "own" the production issue. The customer is included because the issue could be operator error or process incompatibilities.

• One phone call can be made to source equipment needs, such as spare parts.

The goal of the turnkey SMT equipment vendor (to totally automate and integrate) is certainly worthy of consideration. Taken as a whole, the complete design/manufacturing process, which begins at concept and ends with a manufactured system, is very complex. In any large company, it requires thousands of separate steps from beginning to end, including the cooperation of hundreds of individuals and many different departments. Even a small improvement in efficiency in any step of the process can result in a directly measurable increase in profitability. This, plus the guarantee of an increase in quality of the finished product, is the ultimate promise of automation.

Jeffrey Stong is technical manager at Essemtec USA (essemtec.com); sales@essemtec-usa.com.