Epoxy Mold Compound Cleaning Cycle Cleaners & Conditioners

How to Clean Epoxy Molding Compound with Melamine and Rubber Cleaning Sheets


When using Epoxy Mold Com­pound (EMC), what is the prop­er clean­ing pro­ce­dure to fol­low to ensure a prop­er mold clean­ing, while avoid­ing wast­ing valu­able pro­duc­tion uptime? How many shots of melamine and/or mold con­di­tion­er are need­ed for a prop­er clean­ing? These are the stan­dard ques­tions that we get asked reg­u­lar­ly by new process engi­neers and operators.

Below is the rec­om­mend­ed clean­ing procedure:

Please vis­it us at www.caplinq.com to learn more about our whole range of epoxy mold­ing com­pounds includ­ing our semi­con­duc­tor-grade epoxy mold­ing com­pounds, our fiber­glass-rein­forced indus­tri­al mold­ing com­pounds, and our opti­cal­ly clear epoxy mold com­pounds (CMC).

We can also help sup­port you to select and use the prop­er melamine-based epoxy mold clean­ers, as well as rub­ber-based clean­ers and con­di­tion­ers. If you have any oth­er ques­tions about how best to clean your molds, the prod­ucts you can best use to clean them, or the appli­ca­tion meth­ods of these mate­ri­als, please feel free to leave a com­ment below, or don’t hes­i­tate to con­tact us.

About Chris Perabo

Chris is an energetic and enthusiastic engineer and entrepreneur. He is always interested in taking highly technical subjects and distilling these to their essence so that even the layman can understand. He loves to get into the technical details of an issue and then understand how it can be useful for specific customers and applications. Chris is currently the Director of Business Development at CAPLINQ.

21 thoughts on “How to Clean Epoxy Molding Compound with Melamine and Rubber Cleaning Sheets

  1. I’ve read your web­site regard­ing the clean­ing pro­ce­dure here.

    I want to ask the type of melamine and con­di­tion­er that sup­pos­es to be use for the clean­ing, thanks.

  2. @yazid The mate­r­i­al most often used in the indus­try is Nikalet Melamine Mold Com­pound. Con­tact us for pel­let sizes and prices.

  3. hel­lo! i’m a process engi­neer in one of the semi­con­duc­tor com­pa­nies here in the philip­pines. the steps 1 — 4 you have post­ed are the nor­mal die clean­ing in semi­con­duc­tor mold­ing process. but most in the mold­ing process, after die clean­ing, after the oper­a­tor have con­duct­ed 2 shots dum­my, there are pres­ence of incom­plete mold/incomplete fill­ing (or mizyuuten, in japan­ese term) espe­cial­ly in the cor­ners of each cav­i­ty. it will only remove if the operator/technicians/engineers will man­u­al­ly clean the cav­i­ty that are affect­ed by using a cop­per rod. one of our coun­ter­mea­sure is that, we sub­sti­tut­ed the melamine (clean­ing resin) and con­di­tion­er (wax resin) with a rub­ber clean­ing mate­ri­als but after die clean­ing using rub­ber clean­er, there are pres­ence of plas­tic com­pound at the walls of each cav­i­ty. and again, it will only remove if the oper­a­tor will clean man­u­al­ly the affect­ed cav­i­ty. we use KTMC rub­ber clean­er here in our com­pa­ny. can you give me oth­er mak­ers or sup­pli­ers of rub­ber clean­ing mate­ri­als? thanks

  4. I would’t sug­gest rub­ber clean beca­sue that quite high release odor when com­pare with melamine which high risk oper­a­tor get it and accu­mu­late became tox­ic into health.

  5. Yazid

    You can ask Melamine sup­pli­er to get the suite cure time.
    note: Dif­fer­ent melamine sup­pli­er so that dif­fer­ent curetime.…

  6. Hel­lo,

    I am work­ing for a com­pa­ny that is just start­ing to get into plas­tic assem­bly. How often do peo­ple typ­i­cal­ly per­form clean­ing pro­ce­dure (every cou­ple hours, every work­ing shift, every day?) ? I am using Hitachi CEL-9240-HF10 for our mold com­pound and have only been able to achieve rough­ly ~30 shots on our semi auto-mold, but the sup­pli­er says upwards to 100 shots is pos­si­ble. Any sug­ges­tions on how we can improve this? Any feedback/knowledge that would be help­ful on some­one just get­ting into the semi­con­duc­tor indus­try would be help­ful. Thank you

  7. Hel­lo Russell,

    Epoxy mold com­pound clean­ing cycles vary depend­ing on many vari­ables, includ­ing but not lim­it­ed to: epoxy mold com­pound, size of part, age of mold, fre­quen­cy and qual­i­ty of the epoxy mold con­di­tion­ing com­pound and the epoxy mold release agent used. The Hitachi CEL-9240 epoxy mold com­pound is a well-known epoxy for QFP, SOP, QFN, PLCC on lead­frame devices. I agree with the sup­pli­er (Hitachi) that it is pos­si­ble to run upwards of 100 shots before clean­ing, but this depends a lot on how small the parts are and how tight the cav­i­ties are. 

    The first thing I would do is look at the age and qual­i­ty of the molds. Before you start, are the molds new or already pret­ty used? (Old­er molds need more fre­quent clean­ing). Next, how clean are the molds? Are they real­ly very clean before you start run­ning epoxy mold com­pound again? (You should typ­i­cal­ly run 2–3 cycles of clean­ing). And next, are you using any epoxy mold con­di­tion­ing after clean­ing? (Con­di­tion­ing pre-con­di­tions the mold with wax to make clean­ing cycles less fre­quent. Final­ly, are you using any Epoxy Mold Release Agent? (If you use a spray between molds, you will decrease the fre­quen­cy of the mold clean­ing cycles required.

    Caplinq now sup­plies Clean­ers, Con­di­tion­ers and Lubri­cants for Epoxy Mold­ing Com­pounds includ­ing our own brand of Lin­qsheet Mold Clean­ing and Con­di­tion­ing Sheets, our Lin­qWax Car­nau­ba Wax Aerosol Spray and our Lin­qSil Sil­i­cone Mold Release Spray. Please con­tact us for any ques­tions relat­ed to clean­ing or con­di­tion­ing prod­ucts for epoxy or ther­moset molding.

  8. Hey Chris

    Thanks for the feed­back that is much appre­ci­at­ed. May be off top­ic, but I have been try­ing to find a stan­dard in which deter­mines how much des­ic­cants should be used to when de-thaw­ing the mate­ri­als (mold com­pound, clean­er con­di­tion­er). Not sure what would be used to deter­mine that whether it would be amount of mate­ri­als, or size of bag. If any­one had infor­ma­tion on this it would be great­ly appreciated.

  9. Hi Rus­sell,

    Yes, this is off-top­ic, but hap­py to help 🙂 I also do not know of any stan­dard, but I real­ly don’t think it’s nec­es­sary. Epoxy Mold Com­pounds, or Epoxy Mold Con­di­tion­ers should always come inside a plas­tic bag inside a sec­ondary pack­ag­ing (either a card­board box or a plas­tic pail). The thaw time need­ed to thaw even the largest (25kg) pack­ag­ing is 24 hours. You should­n’t thaw either epoxy mold com­pound or Epoxy mold con­di­tion­er longer than this (for 5–10 kg pack­ing 8 hours is also plenty).

    When you take out the box to thaw DO NOT OPEN THE PLASTIC BAG. This is the most impor­tant. Mois­ture can absorb into the epoxy mold com­pound dur­ing the thaw peri­od, but only if the plas­tic bag is open. Mois­ture comes from the con­den­sa­tion of the (warm) atmos­phere onto the (cold­er) plas­tic pack­ag­ing. Mois­ture will not pen­e­trate the plas­tic bag, so there are no addi­tion­al des­ic­cants nec­es­sary. Hope this answers your question.

  10. Hey Chris

    Thanks for the feed­back that helps clear a lot of infor­ma­tion up. Due to pro­duc­tion size being quite small at this moment, as well as not hav­ing a cold room, there are a cou­ple con­cerns that arise for me.

    As a result of our pro­duc­tion size being quite small, we gen­er­al­ly have to weigh out the amount of mate­ri­als from the pack­ag­ing, so we do not waste unused mate­ri­als. As a result, the plas­tic pack­ag­ing is opened to weigh out the mate­ri­als. What method would you con­sid­er best in reduc­ing the prob­a­bil­i­ty of mois­ture get­ting inside the mold com­pounds? As I stat­ed, we do not have a cold room so that is not cur­rent­ly a option.

    Thanks a lot Chris. I just found this blog and have found extreme­ly help­ful infor­ma­tion already.


  11. Glad you find the infor­ma­tion use­ful, Rus­sell. Please come back often 🙂

    I’m con­cerned if you do not have a cold room at all. For small vol­ume pro­duc­tion, even a chest fridge or freez­er is per­fect­ly suit­able. For a cou­ple hun­dred bucks, you should con­sid­er the invest­ment (I’m sure the small vol­umes of epoxy mold com­pound will cost as much!). Any­thing that goes to 10C (stan­dard fridge) is fine, but a ‑20C chest freez­er, will do no harm to the epoxy and can even extend shelf life. If you need to open the pack­ag­ing to weight out mate­r­i­al, you should do this in the cold stor­age. This isn’t the “ide­al” advice as open­ing and clos­ing plas­tic bags is not ide­al (though all small vol­ume man­u­fac­tur­ers do it any­way), but if your epoxy mold com­pound is in the freez­er, you are bet­ter off to open and close the plas­tic in the freez­er. This way, there is no mois­ture as a result of condensation.

    What you could do if this is avail­able to you, is to put the mate­r­i­al you have removed into a “nitro­gen cham­ber” (a so-called dry-box), which is even bet­ter than any des­ic­cant. Con­sid­er­ing you said the vol­umes were small, this should be pos­si­ble. If there is no nitro­gen cham­ber — then I find a des­ic­cant is pret­ty use­less. There won’t be enough time to “suck the mois­ture” out.

  12. Hey Chris

    Great infor­ma­tion. Cur­rent­ly we have a freez­er (-50C) that all the mate­r­i­al is stored in. I am going to see if we can incor­po­rate the dry box, as well as change the pro­ce­dures to weigh­ing the mate­r­i­al in the freez­er itself. 

    In addi­tion, cur­rent­ly we are using trans­fer clean­er + trans­fer con­di­tion­ing pel­lets. As a result, the cav­i­ties of our mold tend to be quite clean, but the out­side of the cav­i­ties itself is start­ing to get dirty. Because we are using the trans­fer clean­ing pel­lets, what meth­ods do peo­ple use in clean­ing the out­side of the cav­i­ties when using clean­ing pel­lets? The rea­son we are using clean­ing pel­lets, is our mold has vac­u­um holes, thus com­pres­sion grade clean­ers + con­di­tion­ers have been clog­ging the vac­u­um holes, and mak­ing it hard to clean. Thanks guys


  13. Hi Rus­sell,

    Weigh­ing the mate­r­i­al in the freez­er is not a ter­ri­ble idea — but ‑50C is a cold place to do it! 

    Trans­fer clean­ing and trans­fer con­di­tion­ing is a stan­dard prac­tice for sure. As you men­tion though, it will not clean the out­side of the cavities.

    Even man­u­fac­tur­ers with vac­u­um holes (most molds do have vac­u­um holes) use com­pres­sion clean­ers to clean the out­side of the cav­i­ties. You do not need to do it every clean­ing cycle, but it’s still a good idea to do it to clean the areas out­side if the runners.

  14. Thanks for you share. we are know that the mould dirty resin con­sists of two lay­ers , the sec­ond lay­ers can be removed by using melamine and sheet, but the first lay­er is abnor­mal stub­born, how to release this lay­er by sim­ply method. thanks.

  15. Hel­lo,

    I have orig­i­nal­ly just been using a trans­fer grade clean­er + con­di­tion­er + two dum­my shots pri­or to going into pro­duc­tion. How­ev­er, it has been noticed that the out­side sur­faces of the mold are start­ing to build up a good amount of stain­ing, and has been trans­fer­ring onto the shoul­der leads of the packages.

    As a result of our mold hav­ing vac­u­um holes, it was rec­om­mend­ed that we use a rub­ber based com­pres­sion sheet vs a melamine based. In terms of reduc­ing the clog­ging in the vac­u­um holes, what can we do to reduce the pos­si­bil­i­ty of the holes get­ting clogged oth­er than turn­ing off the vac­u­um draw?

  16. We have a new prod­uct and it requires overmold,the 1st shot using dum­my the appear­ance was good, no sign of defectt but when we pro­ceed­ed to a good units after mold it becomes more in the sur­face and most like­ly not accept­able any­more. Now my con­cern is is it advis­able to clean the low­er mold chase fre­quent­ly or it has a fre­quen­cy of cleaning,By the way we use dow corn­ing as a rub­ber sheet cleaning.

  17. The fre­quen­cy of clean­ing is depen­dent on many vari­ables includ­ing the type of epoxy mold­ing com­pound used, the design of the mold chase and the clean­ing com­pounds used. Typ­i­cal­ly, the fre­quen­cy is deter­mined by a tri­al-and-error method — start­ing with few­er clean­ings and then going to more reg­u­lar clean­ing. If the mold is cleaned, extend the num­ber of clean­ings done until you get insuf­fi­cient results and then dial it back. If you can advise the Epoxy Mold Com­pound used, the pack­age type and the grade of Dow Corn­ing Rub­ber Clean­ing Sheet, we might be able to advise more specifically.

    Alter­na­tive­ly, CAPLINQ also offers Epoxy Mold­ing Com­pound and Rub­ber Clean­ing Sheets that we have designed to work well together.

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