JÄGER Busi­ness Blog

Lead time to series pro­duc­tion —
When tool­mak­ing leads to delays

08.09.2021   |   Hen­ning Schröer

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There are many rea­sons for project delays in both elas­tomer and plas­tics pro­duc­tion. Deliv­ery prob­lems along the sup­ply chain are often to blame. Par­tic­u­lar­ly at the start of a project, there is a time fac­tor that only a few cus­tomers have in mind, although it accounts for a non-neg­li­gi­ble part of the lead time before the start of series pro­duc­tion: tool­mak­ing. This is much more com­plex for both rub­ber and plas­tic prod­ucts than it might seem. If cus­tomers under­es­ti­mate the man­u­fac­ture of the tool dur­ing devel­op­ment, this puts on-time project com­ple­tion in jeopardy.

Mold­ing tools in rub­ber and plas­tics production

The geom­e­try of the mold­ing tool must exact­ly match the dimen­sions of the mold­ed parts to be pro­duced, includ­ing nec­es­sary tol­er­ances. For this rea­son, a sep­a­rate tool must be man­u­fac­tured for each project accord­ing to a spe­cial cus­tomer draw­ing, which also includes design, man­u­fac­tur­ing and trans­port. In a sense, tool­ing is a project with­in a project and the most impor­tant link along the man­u­fac­tur­ing chain for a func­tion­ing part. Due to the large scale of the man­u­fac­tur­ing process, it is obvi­ous that it often results in delays.

There are four major influ­enc­ing fac­tors that often delay the on-time deliv­ery of the mold (and thus the start of pro­duc­tion of the mold­ed part):

Review and adjust­ment of the design draw­ing cost time

As a rule, cus­tomers cre­ate a design draw­ing of the required mold­ed part before con­tact­ing a pro­duc­tion part­ner such as Jäger — Gum­mi und Kun­st­stoff. How­ev­er, this draw­ing is often focused on the geo­met­ric require­ments of the fin­ished com­po­nent, not on its pro­duc­tion. As a result, cus­tomer spec­i­fi­ca­tions are often not designed for production.

Com­mon prob­lems include miss­ing draft angles or miss­ing radii. Oth­er errors are pro­duc­tion-spe­cif­ic and escape design­ers who are not famil­iar with the material.

One exam­ple is the dif­fer­ent flow behav­ior of rub­ber and plas­tic. Rub­ber is inject­ed cold into the mold and then heat­ed or vul­can­ized, while plas­tic is inject­ed hot and cools/solidifies in the mold. In both cas­es, the raw com­pound behaves fun­da­men­tal­ly dif­fer­ent­ly dur­ing man­u­fac­tur­ing. How­ev­er, the sub­tleties are found with­in the mate­ri­als used. Each mate­r­i­al — whether plas­tic or rub­ber — flows dif­fer­ent­ly dur­ing the injec­tion process. Here, know-how is essen­tial in order to select the type and method of gat­ing, as oth­er­wise var­i­ous defects can occur in the mate­r­i­al of the end prod­uct, e.g. vis­i­ble flow defects.

Devel­op­ment at Jäger

To pre­vent design errors from affect­ing the pro­duc­tion of the mold­ed parts, the pro­duc­er first checks all spec­i­fi­ca­tions and cre­ates a real­is­tic mold con­cept, which is then coor­di­nat­ed with the cus­tomer. How­ev­er, this process takes time. Care is para­mount at this point, because even if molds are sub­se­quent­ly reworked, this extra loop is to be avoid­ed too urgently. 

Com­mu­ni­ca­tion with man­u­fac­tur­ing part­ners increas­es the workload

Only a few pro­duc­ers still man­u­fac­ture tools in-house these days. Instead, they usu­al­ly out­source tasks beyond their own core com­pe­ten­cies to ser­vice providers. This is also the case in tool­mak­ing. As a rule, the man­u­fac­tur­ing part­ners are locat­ed with­in Ger­many. Work­ing with domes­tic ser­vice providers sim­pli­fies com­mu­ni­ca­tion and reduces the orga­ni­za­tion­al effort that results from dif­fer­ent legal frame­works and logis­tics requirements.

In some projects, how­ev­er, the cost pres­sure from the cus­tomer is very high. In such cas­es, it makes sense to out­source tool­mak­ing to low-wage coun­tries. Chi­na is often cho­sen because of its robust steel indus­try and low­er raw mate­r­i­al costs.

The qual­i­ty of the tool is quite com­pa­ra­ble with Ger­man man­u­fac­tur­ers. How­ev­er, the coor­di­na­tion effort is cor­re­spond­ing­ly high­er. Espe­cial­ly if the mold­ing pro­duc­er does not have its own local branch and com­mu­ni­ca­tion takes place across dif­fer­ent time zones. Although coor­di­na­tion with Ger­man part­ners also affects the tim­ing of the man­u­fac­tur­ing project, in an inter­na­tion­al con­text with com­pli­cat­ed projects this delay is sig­nif­i­cant­ly higher.

Case Study: Com­plex plas­tic Hous­ing or elec­tric battery

In our case study, you will learn how we real­ize the high­est mate­r­i­al require­ments despite time pressure. 

The trans­port of the goods must be planned

Anoth­er fac­tor is logis­tics. If the mold is pro­duced by an exter­nal part­ner, trans­port can lead to delays depend­ing on the sit­u­a­tion. Here, too, it depends on whether the mold­ing pro­duc­er is work­ing with a local or an inter­na­tion­al moldmaker.

If the mold is man­u­fac­tured in Ger­many or a neigh­bor­ing EU coun­try, trans­porta­tion usu­al­ly takes rel­a­tive­ly lit­tle time and can often be han­dled by in-house capac­i­ty. How­ev­er, in some cas­es, delays can occur due to weath­er or traf­fic. If the tool­mak­er man­u­fac­tures in Asia, the sit­u­a­tion is dif­fer­ent. Then the trans­port may cost a lot of time. Trans­port­ing the tool by air freight is rel­a­tive­ly quick, but not always pos­si­ble. Espe­cial­ly when there is high cost pres­sure, many com­pa­nies switch to cheap­er trans­port routes, such as sea freight or rail trans­port. The deliv­ery time is cor­re­spond­ing­ly longer.

Check­ing and release of the tool

Tools for mold­ed part pro­duc­tion are pre­ci­sion instru­ments. Even slight devi­a­tions from the design spec­i­fi­ca­tions, espe­cial­ly with tight tol­er­ances, can ren­der the arti­cles pro­duced unus­able. For this rea­son, the tool is thor­ough­ly checked before pro­duc­tion starts.

Sev­er­al par­ties are involved in this task. First, the tool­mak­er him­self checks whether he has imple­ment­ed all spec­i­fi­ca­tions cor­rect­ly. Then, the rub­ber pro­duc­er re-mea­sures spe­cif­ic dimen­sions before installing the mold in the pro­duc­tion line and set­ting it up on the injec­tion mold­ing machine. The cus­tomer of the mold­ed part is not direct­ly involved in this process. How­ev­er, he checks the cor­rect­ness of the mold indi­rect­ly by inspect­ing the sam­ples pro­duced with it and check­ing the ini­tial sam­ple inspec­tion report.

Mea­sure­ments in par­tic­u­lar take time because they have to be very pre­cise. Spe­cial instru­ments are usu­al­ly used for this pur­pose, which can iden­ti­fy the small­est inaccuracies.

In sum­ma­ry

Mold mak­ing is an inte­gral part of any injec­tion mold­ing man­u­fac­tur­ing project, whether rub­ber or plas­tic. Most cus­tomers are aware that an injec­tion mold is need­ed. How­ev­er, they under­es­ti­mate how much effort lies behind its man­u­fac­ture. An injec­tion mold is not a stan­dard com­po­nent, but a pre­ci­sion tool that is made indi­vid­u­al­ly for each job.

Mold man­u­fac­tur­ing is a project with­in a project. It goes through the same process as any oth­er pro­duc­tion, from man­u­fac­tur­ing to release. All of this takes time. Build­ing a tool can­not be short­ened or accel­er­at­ed. That’s why it’s impor­tant to fac­tor it into project sched­ul­ing right from the start.

In the best case, com­pa­nies con­tact a rub­ber man­u­fac­tur­er dur­ing devel­op­ment who is famil­iar with the mate­r­i­al and can con­tribute empir­i­cal val­ues. This makes sched­ul­ing much more robust and min­i­mizes poten­tial prob­lems and errors.

Whitepa­per:
Secure the Start of Production 

Learn which fac­tors influ­ence your SOP! 

Author: Hen­ning Schröer

Hen­ning Schröer stud­ied M. Sc. Indus­tri­al Engi­neer­ing at the Leib­niz Uni­ver­si­ty of Han­nover with a focus on pro­duc­tion engi­neer­ing. He joined Jäger in 2019 as a sales engi­neer for the Hanover site. 

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