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How to pick a top-quality moldmaker(3)

Posted by: Mu Ju 2019-05-02 Comments Off on How to pick a top-quality moldmaker(3)


Lappine of Comet Tool remarks that quality control is becoming an increasingly important issue for moldmakers. "We have to be able to record and maintain traceability of all steel and tooling," he notes. Comet has a full in-house metrology lab to satisfy customers that demand complete certification of all mold components. The in-house metrology department must itself be certified by outside organizations.

Some tooling buyers, such as Nypro, require that their moldmakers have the ability to provide certification of the heat-treating process and of the metallurgical content of the steel. Moldmakers depend on outside sources that specialize in heat treating, including some steel suppliers that perform heat treating as a value-added service.

Tech Mold, as part of a growing industry trend, is in the process of preparing itself for ISO 9000 quality certification (see PT, Jan. ’91, p.53). ISO 9001, which applies to companies that provide design, manufacturing, and product development, is a quality assurance program that makes sure that a company has the systems and documentation in place to produce a quality product. Lomax breaks ISO 9000 into four main questions:

* Where are we going? The answer to that would be defined by a mission statement.

* Who does what? That question would be addressed by a quality manual.

* What do we do? That would be addressed by a procedures manual.

* How well do we what we say we do? That would be answered by quality audits.


A tooling job is complete when a customer’s expectations are met, or even exceeded, is the answer given by several moldmakers. Many of them avoid written guarantees. According to Steve Ballek, v.p. of Ballek Die & Mold in Hoffman Estates, Ill., "There are really no written guarantees from any mold shop in the Chicago area. Most people stand behind their work if it is a reputable shop." He adds that on critical tolerances, his shop machines a tool to be "steel-safe." If required, he will "tune it in" after the initial run and inspection by the molder.

What can a molder reasonably expect from its tool? Lappine of Comet Tool recommends that customers ask toolmakers to give an estimated cycle time. Nypro, for example, does not require a guarantee of cycle time but looks for closeness to its original estimate for that mold. Lappine adds, "There are times in which I will guarantee cycle times, but not too many people are willing to and I’m not always willing to." One reason, he explains, is that he has no control over a customer’s molding operation.

When it comes to expected tool life, Lappine says customers can reasonably expect a minimum guarantee against wear for a million cycles, and he guarantees some of his molds against wear for up to four million cycles.

One key to customer satisfaction may actually lie with the customer. According to Lappine, "One of the biggest mistakes people make when buying molds today is that they look only at the bottom line for the construction of the mold. They don’t take into consideration the bottom line of the project." A mold that costs an extra $5000 may have a 20% faster cycle time, he says.

When weighing competitive quotes, Lappine recommends that customers should compare apples to apples. Often, the price differential between suppliers results from differences in mold design. "Use spec sheets to make sure you are getting the same thing from everyone involved. Compare them to see the differences." For example, one moldmaker may put its water jackets into the cavity, while another may run water through the plate. Both say on paper that they have water cooling, but each method affects cycle time differently.

One last caveat: Dow’s Payson advises customers to be wary of mold shops that underbid on jobs. An unscrupulous shop may deliberately bid low. "They may lose money on the mold, but make money on the ECs !engineering changes^ required to make the mold work." He looks for mold shops whose designers communicate problems beforehand to the customer to avoid unnecessary charges later on.

Profile of Moldmakers’ Capabilities

In order to provide a statistical portrait of the activities and capabilities of North American moldmakers, PLASTICS TECHNOLOGY surveyed 440 moldmaking shops, asking them to score themselves in several key areas. From that number, 116, or 26%, responded to questions about design and manufacturing capabilities, tooling calibration, and customer and supplier relationships. The questions were based on quality criteria suggested by molders and moldmakers.


Of the respondents, 93% build molds for other companies’ use; 7% build them exclusively for their own use; and 20% do both. Injection moldmaking was heavily represented in the survey; 97% of respondents produce injection molds, 80% build hot-runner types when required. Molds for other processes include compression/transfer (40% of respondents), blow molds (28%), thermoforming (18%), and RIM (14%). Blow molds garnered the highest average number of molds (131) produced in a year by a moldmaker. Respondents indicated that they build an average of 58 injection molds per year, about half of which (33) are hot-runner molds.

In addition to building new molds, many provide related services, including mold repair (93%), building prototype molds (86%), and prototype models (48%). A fairly large number do some molding themselves: 71% provide mold sampling/tryout and 38% also perform production molding.

Key markets served by at least half of the mold shops include consumer products (76%); automotive (69%); medical/pharmaceutical (59%); computers/business machines (51%); and appliances/power tools (50%). Others include packaging/food service (48%); recreational/toys (40%); and optical/lenses (19%).

Almost 76% of mold shops that responded are relatively small, with 50 or fewer employees involved in moldmaking; 25% employ 10 or fewer; and 24% employ more than 50. The median is 25 employees. Nearly two-thirds (63%) of the mold shops produce molds weighing under a maximum of 10,000 lb.


CAD/CAM is well represented, with over 90% of respondents indicating they have a system in place. The most common uses of these CAD/CAM systems (by about 90% of respondents) are for programming of cutting-tool paths, core and cavity design, and overall mold-assembly design. Two-thirds of respondents also use CAD/CAM for runner system design.

On the other hand, mold-filling analysis has yet to gain wide acceptance. Only 10% of injection moldmakers perform mold-filling analysis in-house. And even if they obtain outside consulting assistance, less than 13% of moldmakers perform mold analysis on more than half their molds. (The median figure is 20% of their molds use mold analysis.)

We asked which services are performed most commonly (i.e., on more than half of molds built): 89% said design of cores and cavities; 70% said design of runner systems; and 28% said part design.


Of all respondents, 89% said that they perform conventional EDM in-house, while 28% of mold shops are equipped with wire EDM machines. Thirty-five percent indicated that more than half of their cutting machines are CNC controlled, and an equal percentage equip their cutting machines with direct numerical control (DNC). More than half (54%) use a common computer database for tool design, machining, and inspection.

Electronic data interchange (EDI) is fairly well established between moldmakers and their customers. Of the 65% of respondents who said they use EDI, the most common application (60%) is for exchange of CAD information; 14% use it for billing/quoting.

Only about one in four (26%) mold shops that participated in the survey has a formal equipment replacement program. In general, 59% said the majority of their machining equipment is from five to 10 years old. One quarter of respondents said the majority of their equipment was five years old or younger, and 16% said it was 10 years or older.

Median employee profile for responding mold shops is 10% apprentice moldmakers, 20% junior moldmakers, 40% master moldmakers, and 30% specialized machinists. Slightly better than half (52%) of respondents say they have a formal apprenticeship program. Among all respondents, 45 is the median number of hours of training required annually.

On average, about half (51%) of the moldmakers say they calibrate their machining equipment annually, 19% quarterly, 10% monthly, and 13% "as needed." Inspection equipment is checked a bit more often on average: 42% annually, 27% quarterly, 10% monthly, and 10% "as needed." Most moldmakers (86%) calibrate new machining or inspection equipment before use. Not quite half (48%) of shops have written procedures for calibrating equipment, although about two-thirds (63%) train their people in how to follow calibration procedures. Coordinate measuring machines are used for tool inspection by 41% of responding moldmakers.

Twelve percent of respondents indicated that the tightest tolerance that can reliably be kept with their machining equipment was 0.0001 in. About one in four (26%) said they can reliably hold tolerances to 0.0005 in., and another quarter can reliably hold tolerances to 0.001 in. Only 24% use SPC to evaluate machine capability, and only a third train their employees in SPC methods. Slightly less than half (48%) provide temperature/humidity control in their machining areas for the sake of machining quality.


Nearly two thirds (62%) of moldmakers usually receive certification on steel procured from their supplier, and two-thirds ensure full traceability of all mold materials. About the same proportion (61%) certify each heat-treating job, although fewer than half (47%) certify each plating or other surface-coating job. Most (63%) said they perform a full inspection of purchased mold materials.

About 40% of respondents said they have a formal, written quality policy; slightly fewer (36%) have a corporate quality manual, and a bit more (42%) have a separate quality department. On the other hand, two-thirds said they have an on-going program to train their employees in quality. Slightly fewer than half (46%) have a formal program to analyze and reduce customer complaints.

Fifty-two percent of moldmakers said they respond to requests for job quotes in three days or less. A whopping 91% said they deliver better than half of molds on time (most cite engineering changes as the biggest reason for delays). Similarly, 94% said they deliver more than half of new molds at the quoted price. Nearly two-thirds (62%) use a formal production scheduling system, and nearly every respondent (97%) has some sort of record-keeping system for each job.

Moldmakers are somewhat selective in granting certain product guarantees. More than half (52%) said they rarely or never guarantee a cycle time for a finished mold; one-third sometimes guarantee a cycle time and 15% guarantee it often. On the other hand, 62% often guarantee critical part dimensions on a mold, 30% guarantee them sometimes, and 8% rarely or never.

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