Years in the making, Interpower^® rolled out its 1-week U.S. lead times for power cords in 2008. To those acquainted with power cords, 1-week lead times may not sound that impressive. However, industry professionals know that countries and continents have their own worldwide plug patterns. Though much more standardized today, amperage and voltage ratings may vary from continent to continent, country to country. And plug bridges contain blades and pins which vary in dimensions and configurations per each country’s standard.

Add that each country-specific plug must be tested by its own government agency (or an outside agency approved by its government) before the plugs bear the official approval marks of those agencies. As an aside, in North America both UL and CSA can certify components as “recognized,” (separately) or “listed” if approving all of the components of a finished cord set (product). Approval marks symbolize that the manufacturer has met the testing criteria listed in the standards written for the component/product, including raw materials, dimensions, and tolerances such as the length and width of pins and blades and the distances between them—this includes certification from the testing agency set forth in the standards.

Custom-made “Approval Mark” Inserts

Once agency approved, the cord manufacturer making the plug must make a custom-made steel insert engraved with one or more approval marks. The small rectangles of steel (Interpower uses stainless steel) are engraved with appropriate approval marks before the insert is fitted within the mold cavity. The plug or connector is then molded onto a bridge of terminals and thus the mark appears in relief on the face of the molded component via the insert. So, what about the next batch of cords that are for a different country? The molds are quickly changed out adding the appropriate inserts for the new country-specific markings. Different plug bridges made for the new country’s plug pattern are then molded onto NEMA or international cable.

Knowing how countries conduct approval processes is critical to exporting products. Typically, you will need a testing agency’s mark as well as the country’s mark. If you are manufacturing British plugs in the UK, for example, you will need UK approval and the appropriate marks: “ASTA” and “BSI.” ASTA is the testing-certification agency and BSI is the entity creating the standards. As for a British cord set, you would also add VDE on the IEC connector, since VDE is a worldwide testing agency located in Germany and recognized in Europe and beyond.

Besides labor and materials, the financial investment for the marks are mainly two-fold: the cost of testing per the standards at the approval agency’s lab; the cost of the custom-made stainless steel inserts for sizing and engraving. Two examples of approval markings are “UL” and “VDE,” the first North American, the second European. Some testing labs such as UL do the testing along with creating North American standards, as does VDE with European standards.

Teamwork and Quick-change Molding

While manufacturing molded plugs and connectors are in themselves an art, you still need quality cable to turn them into cord sets—what size of AWG or international cable will the plug and connector be molded onto? Do you have approval for the cable? If so, the conductors of the cable must be properly twisted into a length of lay before they are extruded with just the right amount of resin. Once extruded, they are reeled for extrusion once again for the jacketing process, which will be a different color and width than the white extruded conductors. The jacket is thicker and extruded mostly in gray and black, but orange and red are popular for some hospital-grade cords. And after the finished cords are tested, are they to be hanked, coiled, bundled, tied, or individually bagged or boxed? And what customized barcodes get labeled onto the box?

In other words, do you have the all the machines and tooling to manufacture power cord sets, the agency approvals, the shipping and receiving logistics, and the skilled employees to fulfill orders in 1 week? While it may not be rocket science, it’s still an extremely complex process with many moving parts. But all the manufacturing ninja skills are sidelined unless you have raw materials on hand, and good forecasting of how much raw materials you’ll be needing while keeping an ample supply of current inventory, which is touched upon later in this blog.

“Everyone in the company is committed to our 1-week lead times,” said Mike Boyle, Interpower’s Vice President of Manufacturing and Logistics.“It requires having dedicated people in place as well as the high-grade raw materials we use to keep the machines running. We also make sure we carry sufficient stock of our most popular cords. This creates a buffer, allowing us to keep those lead times on most of our country-specific cord sets.”

“We have large and small orders come in—it’s common for us to change out 40 molds per week,” Mike Boyle said, “We can do this because of our quick-change molding process using spring-loaded washers and quick-disconnect waterlines. This not only allows for multiple country-specific orders each week, but also replenishes stock quickly when rebuilding inventory.

“Other molders may have to unbolt the entire mold, which is a far more labor-intensive and time-consuming process. Our quick-change mold process plays a major role in offering our unique 1-week lead times on custom orders, and same-day shipping on in-stock products. By changing molds and colors on the fly, we can keep diversifying our product line.”

The Software Wizard Behind the 1-week Curtain

Efficiency, tooling, and experienced molders are the primary reasons for 1-week lead times. But with such a diverse product line, the constant ebb and flow of raw materials, and the in-stock status of every cord and component in real time, an efficient inventory management system is needed to track it all and to update every component and cord set in real time. So, the wizard behind the 1-week curtain? Interpower uses an algorithmic software system to track manufactured cords, cord sets, and components inputted into the system as stock. The stock varies daily, depending on the number of cords, cord sets, and components that ship. Besides tracking the number of products, the system also looks historically at orders/trends of the past 12 months, which helps establish stock baselines for upcoming months.

While manufacturing, customer service, and shipping rely on the system’s reporting, it’s a must-have for purchasers tracking down raw materials to the ends of the earth—without raw materials, reporting would be next to useless for a power cord manufacturer. Because Interpower offers “Blanket” ordering, customers can lock in cord prices for 12 months. If a company blanket orders cords on January 1, they don’t have to order until December 31.

“In a report, we may show spikes with specific cord sets,” Larry Utterback said, Interpower’s Purchasing Manager. “So, we’ll run another report and see what we can see—is this just a one-time order, or a buying pattern by one or more customers? As for raw materials, we take a much closer look at that when cord and component demand takes us below our safety stocks.” If North American, British, and Japanese cord sets (pick a continent/country) just shipped, the software subtracts those from inventory creating an adjusted number in real time.

According to Boyle, the system updates every five minutes. “Our software system gives us the vital information we need to know exactly what cord sets need to be manufactured for restock and when. Trying to do that on paper would be time-consuming and prone to record-keeping errors—that’s a lot of data.” Looking at the Master Schedule Detail Inquiry is looking at columns of numbers topped by a paragraph of categories and acronyms: Item number; Qty on Hand; Stat; PVC; Plan Orders; Time Fence; Safety Time; Safety Stk; Min Ord; Max Ord . . . on and on. Learning what everything means and how to use it to mine invaluable data via customized reports can take months if not years to master, but well worth the learning curve.

To keep up with its predetermined buffer or safety stock, the program is constantly updating as to what is happening in real time. The program ensures every country-specific power cord set to accessory power strips and power distribution units, and IEC 60320 products: jumper cords, connectors, plug connectors, inlets and outlets, are tracked and forecasted. By offering “Scheduled” orders to customers—orders placed to automatically ship at different times throughout the year—the inventory program lets manufacturing staff know when orders are approaching the built-in deadline, and lets them see in real time raw material amounts and what cords sets and components need restocking as soon as items are picked and shipped—the software automatically updates all important fields, acting as a “fail-safe” so that manufacturing always has the materials they need, ensuring Interpower’s 1-week lead time is met.

Just as impressive as the software is Interpower’s protocol of continually testing its cord sets and components despite their 1-week lead time—dielectric withstand testing or high-potential testing (hipot), continuity testing, and ground testing with inspections after each stage of the manufacturing process. Overseas companies churning out millions of power cords each year are not renowned for running their cords through a battery of tests before shipping them out. “We test more than the standards require,” Interpower Product Development Manager Ron Barnett said. “We do so because it lends better reliability to our design.”