With deployment cost of a surface mount technology (SMT) machine ranging between $50,000 and $300,000, it is imperative that proper care should be taken for their timely maintenance and repairs to avoid failures. The cause of failures can be grouped into four major categories—man, machine, method and materials. Man as a failure source can occur from lack of training or experience, human error or poor supervision. Machine as a failure source can occur from poor maintenance, equipment used beyond its design criteria or machinery that is old or outdated. Methods as a failure source can occur from lack of supervision. It is therefore essential to avail the right maintenance service to avoid such failures.
By Himanshu Yadav
Sunday, August 28, 2011: “As the idea behind using SMT machines is rapid output with zero error, thus their maintenance plays a very important part in production,” says Prasad Gurjal, managing partner, Drive Technologies, a company engaged in sales and service of capital goods for PCB assembly.
Yogesh Suryavanshi, vice president, operations & service support, NMTronics India Pvt Ltd, a provider of machines, solutions and services to the electronics manufacturing industry, adds, “An SMT machine is meant to operates continuously for 24×7 with accuracy in placement and with minimal breakdowns. With this kind of performance requirement, its maintenance is very essential. Manufacturers of SMT machines give guidelines for their daily, weekly, monthly and quarterly maintenance and adhering to these guidelines enhances their performance, working life and the quality of end products.”
Technical problems
Common technical problems occurring in SMT machines are print shift, component drop, rejection, soldering problems like dry solder, bridging, problems pertaining to software and vacuum path, failure of control circuits and power supply. As Meghnad Sudhirchandra Shah, managing director, Frontline Electronics, puts it, “Feeders require regular maintenance. Calibration of machines, which can be done only by trained service technicians of the distributor, is also very important.”
According to Gurjal, shift in accuracy in case of printers and placement machines and changes in temperatures in case of reflows are some other technical problems faced by EMS companies. These can be caused due to design and manufacturing defects or simply due to wear and tear. Erratic power conditions also cause problems in these machines.
Types of maintenance required
Traditional maintenance practice includes repair or replacement of machine parts. However, besides this commonly accepted practice, many other steps can be taken to reduce machine degradation and failures. For instance, when a machine is severely degraded, the throughput setting of the machine can be lowered so that it runs in a less loaded state. As the degradation is slowed down due to this step, the machine can stay in production, albeit at a lower rate, until repair or replacement is done.
To take care of technical problems and enhance the life of machines, usually two types of maintenance are offered by service agents—preventive maintenance and breakdown maintenance. Preventative maintenance, as the name suggests, is done by maintaining a proper record of machines or certain parts to determine the time of their replacement. If this action is performed routinely, unscheduled downtime could be reduced dramatically and the facility’s efficiency and profitability can be increased many folds. It is usually done through various analytical techniques to determine when the failure is approaching. In this manner, action can be taken if any imminent failure is approaching.
Breakdown maintenance is done when the machine starts malfunctioning or takes a shutdown. When a part or machine breaks down, the root cause has to be identified and a corrective action has to be taken. This type of maintenance is avoidable as manufacturers may lose production and incur loss until the machine is fully functional.
Manufacturers take up both types of maintenance as per their requirement, however, frequency of the second type keeps increasing depending upon the machine’s condition and vintage.
Suryavanshi shares, “Preventive maintenance should be done periodically for ensuring continued satisfactory performance. We advise the customers to regularly check the health of their machines, i.e., predictive maintenance and the parts should be replaced before they get completely worn out so that machine breakdown can be minimised which can halt the entire operation. Breakdown maintenance can be minimised by regular machine health checks.”
According to Gurjal, regular preventive actions like changing consumables, calibration and shift in program parameters can be carried out to avoid machine failures. “We take three steps to offer the right solution to our customer—we offer modular or simple designs, proper training to user on maintenance and a cost-effective service support with timely backup in terms of advice or personnel visits, if necessary.”
As SMT machines are costly, it is advisable to seek an expert help for their maintenance. But since getting an expert help is an expensive affair and only companies having several SMT lines can afford it, smaller companies having only one or two line can train their in-house service engineers to take care of the maintenance work. Basic maintenance can easily be done by trained in-house engineers.
Cost of maintenance
The maintenance cost of an SMT machine depends on the type of problem and its age. As Shah puts it, “When we had old machines, we were spending about Rs 15 lakh a year on spares, transportation, annual maintenance contract (AMC) and engineer visits.”
According to Subhash Goyal, managing director, Digital Circuits Pvt Ltd, a manufacturer of high quality PCB assemblies, the maintenance can cost about 10 per cent of the SMT machine cost. “It increases with the age of machine,” he adds.
The cost of AMC is also usually 10 per cent of the machine cost, but in older machines it is more than the new ones. Parts are not included in the maintenance cost and customers may have to buy them on their own.
Gurjal advises, “If manufacturers take regular care of their machines, the maintenance may not be very costly. But if ignored completely, it can lead to major and costly interruptions in production.”
Services offered by vendors
Many companies hire their own service engineers and take support from authorised agents of machine manufacturers like NMTronmics, Trans-Tec, Bergen Associates Pvt Ltd, Prosem Technology India Pvt Ltd and Juki India Pvt Ltd.
“We train fresh graduates to take care of maintenance, however, we also take the AMC support from Prosem Technology and American Tech,” says Shah.
SMT vendors offer two types of after sales services—AMC support, which companies give to authorised agents of the machine manufacturers and pay per call support. Under the AMC support, complete maintenance service is provided excluding the cost of spare parts, for which clients have to pay extra. Under pay per call service, clients have to pay for each service call or engineer visit. The clients, under this service, may be required to pay vendors on per day basis and also the cost of spares.
Usually companies prefer signing AMC, under which service engineers of vendors make quarterly visits. They check functioning of the machines and perform tasks like cleaning, greasing, tuning, checking accuracy, adjustment of moving parts, calibration, etc.
However, if a manufacturing company hasn’t signed an AMC with the manufacturer then it depends on the company whether it wants to call a service engineer of the manufacturer or do the maintenance through its in-house engineers.
Choosing the right support
While selecting the type of service support, it is advisable that companies should take the number of machines being used into consideration. “If a firm has more number of machines of the same make and have experienced staff to handle the maintenance work, it can opt for pay per visit service. However, new customers who have only one or two SMT lines may go for AMC,” shares Goyal.
Gurjal says, “It is advisable to customers to do the basic maintenance on their own. This is the fastest and surest form of support as it makes the user fully independent.”
According to Suryavanshi, the basic maintenance should be performed by the customer only if the staff handling the machines are trained by authorised agents or manufacturers.
Second hand machines
Second hand machines provide economic advantage to manufacturers in terms of low initial cost of investment. However, it is advisable that they should evaluate manufacturing date, brand, model, number of hours run, etc, before making the purchase. These factors are very important and contribute significantly to the maintenance cost.
Suryavanshi explains, “Second hand machines require more maintenance as compared to new machines because of aging machine parts. Service agents have to replace them as per the recommendations from the machine manufacturer”. Goyal adds, “For second hand machines it is advisable that one should opt for AMC.”
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