The impact of surface roughness on conformal cooling channels for injection molding

Ci a ion: Hanzlik, J.; Vanek, J.; Pa a, V.; Senke ik, V.; Polasko a, M.; K uzelak, J.; Bedna ik, M. The Impac o Su ace Roughness on Con o mal Cooling Channels o Injec ion Molding. Ma e ials 2024,17, 2477. h ps://doi.o g/10.3390/ ma17112477 Academic Edi o s: F anz E. Webe and Alexande Yu Chu yumo Recei ed: 17 Ap il 2024 Re ised: 3 May 2024 Accep ed: 16 May 2024 Published: 21 May 2024 Copy igh : © 2024 by he au ho s. Licensee MDPI, Basel, Swi ze land. This a icle is an open access a icle dis ibu ed unde he e ms and condi ions o he C ea i e Commons A ibu ion (CC BY) license (h ps:// c ea i ecommons.o g/licenses/by/ 4.0/). ma e ials A icle The Impac o Su ace Roughness on Con o mal Cooling Channels o Injec ion Molding Jan Hanzlik 1, Ji i Vanek 1,* , Vladimi Pa a 1, Voj ech Senke ik 1, Ma ina Polasko a 1, Jan K uzelak 2 and Ma in Bedna ik 1 1Facul y o Technology, Tomas Ba a Uni e si y in Zlin, Va ecko a 5669, 760 01 Zlin, Czech Republic; [email p o ec ed] (J.H.); [email p o ec ed] (V.P.); [email p o ec ed] (V.S.); [email p o ec ed] (M.P.); [email p o ec ed] (M.B.) 2Facul y o Chemical and Food Technology, Slo ak Uni e si y o Technology in B a isla a, Radlinskeho 9, 812 37 B a isla a, Slo akia; [email p o ec ed] *Co espondence: [email p o ec ed] Abs ac : Injec ion molding echnology is widely u ilized ac oss a ious indus ies o i s abili y o ab ica e complex-shaped componen s wi h excep ional dimensional accu acy. Howe e , chal- lenges ela ed o injec ion quali y o en a ise, necessi a ing inno a i e app oaches o imp o emen . This s udy in es iga es he in luence o su ace oughness on he e iciency o con o mal cooling channels p oduced using addi i e manu ac u ing echnologies, speci ically Di ec Me al Lase Sin- e ing (DMLS) and A omic Di usion Addi i e Manu ac u ing (ADAM). Th ough a combina ion o expe imen al measu emen s, including su ace oughness analysis, scanning elec on mic oscopy, and cooling sys em low analysis, his s udy elucida es he impac o su ace oughness on coolan low dynamics and p essu e dis ibu ion wi hin he cooling channels. The esul s e eal signi ican di e ences in su ace oughness be ween DMLS and ADAM echnologies, wi h co esponding e ec s on coolan low beha io . Following ha ac , his s udy shows ha when cooling channels’ su ace oughness is lowe ed up o 90%, he educ ion in coolan media p essu e is lowe ed by 0.033 MPa. Reg ession models a e de eloped o quan i a i ely desc ibe he ela ionship be ween su ace ough- ness and key pa ame e s, such as coolan p essu e, Reynolds numbe , and low eloci y. P ac ical implica ions o he op imiza ion o injec ion molding cooling sys ems a e discussed, highligh ing he impo ance o in o med decision making in echnology selec ion and pos -p ocessing echniques. O e all, his esea ch con ibu es o a deepe unde s anding o he ole o su ace oughness in injec ion molding p ocesses and p o ides aluable insigh s o enhancing cooling sys em e iciency and p oduc quali y. Keywo ds: injec ion molding; con o mal cooling channels; addi i e manu ac u ing; su ace oughness; eg ession; ADAM; DMLS 1. In oduc ion Injec ion molding echnology s ands as one o he mos pe asi e and con inually ad ancing me hods o p ocessing plas ics. I s applica ions span a ious indus ial sec- o s, no ably, he au omo i e, ae ospace, and de ense indus ies. The echnology’s p ima y ad an age lies in i s capabili y o ab ica e complex-shaped componen s wi h excep ional di- mensional accu acy, especially in high-se ies p oduc ion. This encompasses he p oduc ion o hin-walled and hick-walled componen s, as well as p oduc s wi h complex geome ies. Howe e , challenges conce ning injec ion quali y can a ise du ing he p oduc ion o ce ain componen s, necessi a ing a en ion [1–3]. Add essing such challenges o en in ol es employing specialized injec ion molding me hods, like mul i-componen injec ion molding o injec ion comp ession molding (ICM). On he o he hand, when adi ional injec ion molding mus be used, high equi emen s Ma e ials 2024,17, 2477. h ps://doi.o g/10.3390/ma17112477 h ps://www.mdpi.com/jou nal/ma e ials Ma e ials 2024,17, 2477 2 o 15 on mold design a e p esen , especially on he cooling sys em design, o ensu e uni o m empe a u e dis ibu ion ac oss he p oduc su ace. Tempe a u e uni o mi y plays a pi o al ole in ensu ing dimensional s abili y and minimizing esidual s esses. Howe e , con en ional manu ac u ing me hods may all sho in ensu ing empe a u e uni o mi y o uniquely shaped p oduc s, p omp ing he adop ion o con o mal cooling acili a ed by addi i e manu ac u ing echnologies. Following ha ac , he usage o con o mal cooling in he injec ion molding design is s ill highe , bu p oblems connec ed o an addi i e manu ac u ing echnology, such as su ace oughness, ha e no been ex ensi ely esea ched in his ield [1–4]. Cu en esea ch p edominan ly e ol es a ound con o mal cooling, wi h e o s ocused on enhancing cooling sys em e iciency. Se e al s udies by Venka esh e al., Deepika e al., Jahan e al., Dimla e al., Pa k e al., and Shen e al. ha e compa ed con en ional cooling me hods wi h hose employing addi i e manu ac u ing echnologies, p ima ily h ough simula ions due o he ela i ely high cos o addi i e manu ac u ing o s eel pa s [ 1 – 6 ]. As men ioned be o e, he con o mal cooling applica ion has he closes ma ch wi h pa s ha equi e p ecise dimensional s abili y and quali y such as op ical pa s [ 7 – 15 ]. Howe e , addi i e manu ac u ing p esen s i s own challenges, such as low-quali y su aces and high oughness, which can impede low in cooling channels and hinde hea ans e , as men ioned by Han e al., Gala i e al., and Babu e al. [ 16 – 18 ]. This ac is closely connec ed wi h he p inciple o addi i e manu ac u ing i sel . Fo example, Di ec Me al Lase Sin e ing (DMLS) c ea es he s uc u e by sequen ially deposi ing laye s o mic oscopic g ains and using high-powe lase beams o selec i ely mel he powde g ains in each laye . Among o he s, his ype o echnology is also used in he nuclea ene gy indus y o i s p ecision [ 19 , 20 ]. One o he main challenges o he accep ance o DMLS in con o mal cooling design is he appea ance o mic oscopic po osi y de ec s in 3D-p in ed me al s uc u es. Such po es a e an a i ac o he me al addi i e manu ac u ing p ocess in ol ing apid mel ing and solidi ica ion wi hou well-de ined bounda y condi ions [ 21 ]. Depending on he shape, size, and o ien a ion ela i e o s uc u e su aces, po osi y de ec s could lead o ma e ial c ack o ma ion and cause s uc u al ailu e [ 22 – 24 ]. Scanning elec on mic oscopy (SEM) is a sui able me hod o de e mining how hese de ec s could be de ec ed [25]. As ano he op ion, ADAM echnology has g ea applica ion po en ial in his ield and can be used in con o mal cooling p oduc ion. Ano he aspec ha could be posi i e is ha ADAM does no ha e as high sa e y equi emen s as DMLS echnology. Howe e , DMLS is s ill he mos widely used echnology in he ield o con o mal cooling, bu ADAM echnology could be a sui able al e na i e me hod o con o mal cooling manu ac u ing. Ne e heless, su aces o 3D-p in ed s uc u es exhibi e y low quali y wi h high alues o su ace oughness ei he in he use o DMLS o ADAM echnology [26,27]. DMLS echnology is commonly used o manu ac u ing injec ion molding con o mal cooling sys ems, and on he o he hand, ADAM echnology is no o en used in his ield bu has g ea po en ial in his applica ion. Howe e , ADAM echnology equi es o he addi ional s eps a e p in ing, such as washing ou he binde . This can cause he c ea ion o ai capsules inside he pa , which has a nega i e impac on he cooling e ec i i y. This ac is no in he scope o his s udy, and su ely u u e esea ch is necessa y. Due o hese aspec s, his s udy is ocused jus on hese wo ypes o AM echnologies and he su ace oughness connec ed wi h hese wo ypes o AM echnologies [26,27]. To op imize addi i e echnologies o injec ion mold cooling, u he p ocessing o channel su aces o educe oughness is impe a i e, and hese ac s a e discussed by Han e al., Gün he e al., and Dumas e al. [ 28 – 30 ]. As con en ional ypes o su ace inishing a e no sui able o use on in e nal su aces, such as cooling channels, on he o he hand, Ab asi e Flow Machining (AFM) eme ges as a sui able me hod o inishing in e nal channels p oduced using addi i e echnologies [ 31 – 34 ]. Howe e , AFM echnology needs o be deeply esea ched in he ield o injec ion molding. Ma e ials 2024,17, 2477 3 o 15 O e all, he main ask o his s udy is o e i y he in luence o he cooling channels’ su ace oughness made by DMLS and ADAM echnology on he o al cooling sys ems’ e ec i i y and closely desc ibe a possible bene i o he usage o inishing ope a ions o he in e nal su aces o he pu pose o lowe ing su ace oughness. 2. Ma e ials and Me hods 2.1. O e iew o he Expe imen The expe imen al pa is p ima ily ocused on how su ace oughness in luences he e iciency o he con o mal cooling channels. Howe e , his expe imen con ains a oughness measu emen o he es specimens made by addi i e echnologies and also deals wi h a cooling channel low analysis and e alua ion o he measu ed da a. 2.2. Ma e ials and Equipmen The choice o which ma e ial can be used o he es specimens is limi ed by addi i e echnology o he ac ha he p oduc ion o he injec ion mold ca i ies uses mainly ool s eels. All hese aspec s had o be aken in o mind and applied o he choice o ma e ial. Following he ac s, he ool s eel was chosen. The selec ed echnologies and equipmen o he ab ica ion o he es specimens a e EOS M 290 (Di ec Me al Lase Sin e ing—DMLS echnology, EOS GmbH, K ailling, Ge many) and Ma k o ged Me al X (A omic Di usion Addi i e Manu ac u ing—ADAM echnology, Ma k o ged, Wal ham, MA, USA). Roughness measu emen s we e pe o med using a Zygo New iew 8000 op ical su ace p o ile (Lambda Pho ome ics, Ha penden, UK). Howe e , o success ul measu emen , he es specimens had o be u ned using he DMG MORI-NTX 1000 CNC machining cen e o u ning and milling (DMG MORI USA, Ho man Es a es, IL, USA). Scanning elec on mic oscopy images we e pe o med using Phenom XL G2 (The mo Fishe Scien i ic, Wal ham, MA, USA). Cooling sys em low analysis was pe o med using Moldex3D ( e sion R14.0). 2.3. Tes Specimens’ Design Real injec ion mold ca i ies made by addi i e echnology a e ela i ely expensi e in con as o con en ional manu ac u ing. In e nal su ace oughness measu emen equi es he des uc ion o he injec ion mold ca i y. Due o his ac , he es specimens we e designed. Howe e , he idea o he es specimen design is inspi ed by he esea ch o Han e al. [ 30 ]. These specimens subs i u e eal injec ion mold cooling channels. Con o mal cooling channels a e made in hese es specimens. The diame e o he cooling channel in his es specimen is 3 mm, and he channel has a helix pa e n wi h a pi ch o 10 mm. Machining o he es specimen is equi ed o success ul su ace oughness measu e- men . Tu ning on a machining cen e was chosen as he app op ia e me hod o his s ep. Machined es specimens a e shown in Figu e 1. 2.4. In e nal Su ace Roughness Measu emen As was men ioned be o e, one o he main goals o his esea ch was o measu e he in e nal su ace oughness o he es specimens, simula ing eal con o mal cooling channels. I was c ucial o se a measu emen p ocedu e. Fi s o all, ab ica ed es specimens had o be u ned on he CNC machine because o exposu e o he cooling channel inside o he es specimen. Nex , he exposed cooling channel was scanned by an op ical su ace p o ile along i s leng h, and his means ha each es specimen (specimen A—DMLS, specimen B—ADAM) was measu ed in i e di e en places. E e y one o he i e measu emen s was ansla ed om a cu ed su ace o a la su ace and sliced up o i y slices. Righ a e , pa ame e s such as a e age oughness (Ra) and p o ile heigh (Rz) we e e alua ed. The Rz pa ame e is especially impo an o ollowing cooling analyses. I is ob ious ha high peaks in he su ace oughness a ec he low beha io o coolan media h ough he channel. Ma e ials 2024,17, 2477 4 o 15 Ma e ials 2024, 17, x FOR PEER REVIEW 4 o 16 (a) (b) Figu e 1. Tes specimens made by DMLS echnology: (a) ab ica ed es specimens (ou e diame e is 20 mm and heigh o he specimen is 40 mm); (b) machined es specimens p epa ed o in e nal su ace oughness measu emen . 2.4. In e nal Su ace Roughness Measu emen As was men ioned be o e, one o he main goals o his esea ch was o measu e he in e nal su ace oughness o he es specimens, simula ing eal con o mal cooling chan- nels. I was c ucial o se a measu emen p ocedu e. Fi s o all, ab ica ed es specimens had o be u ned on he CNC machine because o exposu e o he cooling channel inside o he es specimen. Nex , he exposed cooling channel was scanned by an op ical su ace p o ile along i s leng h, and his means ha each es specimen (specimen A—DMLS, specimen B—ADAM) was measu ed in i e diffe en places. E e y one o he i e meas- u emen s was ansla ed om a cu ed su ace o a la su ace and sliced up o i y slices. Righ a e , pa ame e s such as a e age oughness (Ra) and p o ile heigh (Rz) we e e al- ua ed. The Rz pa ame e is especially impo an o ollowing cooling analyses. I is ob i- ous ha high peaks in he su ace oughness affec he low beha io o coolan media h ough he channel. 2.5. Scanning Elec on Mic oscopy Scanning elec on mic oscopy could e eal po osi y de ec s in he specimens. In his case, mul iple images o he unco e ed cooling channel o bo h specimens A and B ha e been aken. The ol age used du ing measu emen was 10 kV. 2.6. Cooling Sys em Flow Analysis Pe o ming he cooling sys em analysis was he nex s ep in his esea ch. I was im- po an o closely simula e he p ocess o he in e nal su ace inishing because he Rz pa ame e o he inished su ace oughness o he es specimens’ cooling channels is un- known. To achie e his, he de aul alue o he Rz pa ame e was se as he alue eached by he su ace oughness measu emen men ioned abo e. This de aul alue was lowe ed by 10% un il i eached a 90% smalle alue o Rz. Fo each alue o he Rz pa ame e , a single analysis was compu ed. O he p ocess pa ame e s we e cons an in all analyses. Cooling channel analysis p o ides selec ed da a, such as p essu e along he cooling ci cui o coolan media low eloci y. I is impo an o men ion ha all he analyses we e pe o med on he eal injec ion molded op ical pa . Figu e 1. Tes specimens made by DMLS echnology: (a) ab ica ed es specimens (ou e diame e is 20 mm and heigh o he specimen is 40 mm); (b) machined es specimens p epa ed o in e nal su ace oughness measu emen . 2.5. Scanning Elec on Mic oscopy Scanning elec on mic oscopy could e eal po osi y de ec s in he specimens. In his case, mul iple images o he unco e ed cooling channel o bo h specimens A and B ha e been aken. The ol age used du ing measu emen was 10 kV. 2.6. Cooling Sys em Flow Analysis Pe o ming he cooling sys em analysis was he nex s ep in his esea ch. I was impo an o closely simula e he p ocess o he in e nal su ace inishing because he Rz pa ame e o he inished su ace oughness o he es specimens’ cooling channels is unknown. To achie e his, he de aul alue o he Rz pa ame e was se as he alue eached by he su ace oughness measu emen men ioned abo e. This de aul alue was lowe ed by 10% un il i eached a 90% smalle alue o Rz. Fo each alue o he Rz pa ame e , a single analysis was compu ed. O he p ocess pa ame e s we e cons an in all analyses. Cooling channel analysis p o ides selec ed da a, such as p essu e along he cooling ci cui o coolan media low eloci y. I is impo an o men ion ha all he analyses we e pe o med on he eal injec ion molded op ical pa . Analysis Pa ame e s Selec ed analysis pa ame e s we e cons an in all pe o med analyses and a e men- ioned in Table 1below. Table 1. Selec ed analysis pa ame e s. Pa ame e Channel diame e 4 mm Coolan medium Wa e (90 ◦C) De ined low a e 6 L/min Mesh ype Volume ic Elemen ype Te a Numbe o elemen s 172,374 Bad elemen 0 Ma e ials 2024,17, 2477 5 o 15 Table 1. Con . Pa ame e Sol e S anda d Analysis ype 3D solid cooling channel Tu bulence modeling Yes Cooling channel mesh aspec a io ange 0.7–1 3. Resul s 3.1. In e nal Su ace Roughness Measu emen The a i hme ic mean o he Rz pa ame e was selec ed as a cha ac e is ic s a is ic pa ame e used o analysis. I s s a is ical signi icance was e i ied by es ima ing he coe icien s o a ia ion. Nex , he es ima ed a i hme ic means we e ecalcula ed o alues o ans o med a i hme ic means using Box–Cox ans o ma ion, which is commonly used in enginee ing p ac ice o his pu pose [35]. The c ea ed su ace scan can be in e p e ed as ha ing a plane h ough he su ace, which is in e p e ed as a ze o in he scale on he igh . Howe e , his is a ze o de e mined by s a is ical me hods, namely, he leas squa es me hod. This means ha all posi i e oughness alues a e scaled up o a maximum, which is colo ed ed, while alues below he plane a e scaled in g een and blue. A highe sa u a ion o a gi en colo o colo combina ion hen indica es a g ea e dis ance om he ze o plane. A p ojec ion o he measu ed da a o specimen A is shown in Figu e 2. The opology o he su ace made by DMLS echnology is shown in Figu e 2, as well as alues o he su ace oughness. Ma e ials 2024, 17, x FOR PEER REVIEW 6 o 16 Figu e 2. P ojec ion o he measu ed da a o specimen A con aining colo scale. Figu e 3. P ojec ion o he measu ed da a o specimen B con aining colo scale. Da a in Figu e 4 p o e ha he su ace o specimen A and specimen B is opologically diffe en , and his is caused by a ype o addi i e echnology. I is ob ious ha wo opo- logically diffe en su aces a e in he same gene al ange o Rz and a e no ex emely di - e en om each o he . Figu e 2. P ojec ion o he measu ed da a o specimen A con aining colo scale. Figu e 2shows he maximal and minimal measu ed alues o su ace oughness. In his case, he maximal alue is 32.83 µ m, and he minimal alue is − 31.67 µ m. High peaks o he measu ed su ace a e colo ed ed. Figu e 3shows he maximal and minimal alues o he measu ed su ace. I is ob ious ha he maximal alue is 29.68 µ m and he minimal alue is − 31.60 µ m. As was men ioned be o e, he opology o specimen B’s su ace is d ama ically di e en in compa ison o he su ace o specimen A. Howe e , his ype o su ace shown in Figu e 3closely co esponds wi h ADAM echnology. Ma e ials 2024,17, 2477 6 o 15 Ma e ials 2024, 17, x FOR PEER REVIEW 6 o 16 Figu e 2. P ojec ion o he measu ed da a o specimen A con aining colo scale. Figu e 3. P ojec ion o he measu ed da a o specimen B con aining colo scale. Da a in Figu e 4 p o e ha he su ace o specimen A and specimen B is opologically diffe en , and his is caused by a ype o addi i e echnology. I is ob ious ha wo opo- logically diffe en su aces a e in he same gene al ange o Rz and a e no ex emely di - e en om each o he . Figu e 3. P ojec ion o he measu ed da a o specimen B con aining colo scale. Da a in Figu e 4p o e ha he su ace o specimen A and specimen B is opologically di e en , and his is caused by a ype o addi i e echnology. I is ob ious ha wo opologically di e en su aces a e in he same gene al ange o Rz and a e no ex emely di e en om each o he . Ma e ials 2024, 17, x FOR PEER REVIEW 7 o 16 Figu e 4. Compa ison alues o he Rz pa ame e o specimens A and B. A1–A5 and B1–B5 ep e- sen epea abili y o he measu emen . Table 2 shows alues o ans o med a i hme ic means o he Rz pa ame e , and hese alues a e used du ing analyses as de aul alues o he Rz pa ame e . Table 2. Values o ans o med a i hme ic means o he Rz pa ame e . Pa ame e Specimen A (DMLS) Specimen B (ADAM) Rz [µm] 21 34 3.2. Scanning Elec on Mic oscopy A dense and uni o m mic os uc u e is a key o efficien cooling in injec ion mold inse s, as i ensu es high he mal conduc i i y. Typically, a ine-g ain s uc u e wi h low po osi y is p e e ed o op imal hea ans e . Inco po a ing complex geome ies, like con o mal cooling channels, can also imp o e cooling efficiency. The manu ac u ing p o- cess pa ame e s a e also c i ical in achie ing he desi ed mic os uc u e. Resul s ob ained by SEM ma ch wi h he measu emen s o in e nal su ace oughness measu emen s. Specimen A shows he ype o su ace ha co esponds wi h a su ace c ea ed by DMLS echnology and does no show any signi ican ype o po osi y de ec . This ype o su ace can be seen in Figu e 5. This ype o AM echnology shows ha su ace s uc u e can con ain unmel ed pa icles o he me al powde . This ac also can be seen in Figu e 5. Figu e 6 shows he su ace o specimen B made by ADAM echnology. As can be seen, he su ace is apidly diffe en in con as wi h specimen A. SEM images o specimen B do no show any ype o po osi y, which could lead o coolan media leakage in o he injec ion mold ca i y. The su ace s uc u e o specimen B shows ob ious signs o laye s. This is caused by ADAM echnology i sel . The p inciple o ADAM echnology is ha pa s a e p in ed om ilamen and hen sin e ed, and he p inciple is simila o FDM echnology. Figu e 4. Compa ison alues o he Rz pa ame e o specimens A and B. A1–A5 and B1–B5 ep esen epea abili y o he measu emen . Table 2shows alues o ans o med a i hme ic means o he Rz pa ame e , and hese alues a e used du ing analyses as de aul alues o he Rz pa ame e . Table 2. Values o ans o med a i hme ic means o he Rz pa ame e . Pa ame e Specimen A (DMLS) Specimen B (ADAM) Rz [µm] 21 34 Ma e ials 2024,17, 2477 7 o 15 3.2. Scanning Elec on Mic oscopy A dense and uni o m mic os uc u e is a key o e icien cooling in injec ion mold inse s, as i ensu es high he mal conduc i i y. Typically, a ine-g ain s uc u e wi h low po osi y is p e e ed o op imal hea ans e . Inco po a ing complex geome ies, like con o mal cooling channels, can also imp o e cooling e iciency. The manu ac u ing p ocess pa ame e s a e also c i ical in achie ing he desi ed mic os uc u e. Resul s ob ained by SEM ma ch wi h he measu emen s o in e nal su ace oughness measu emen s. Specimen A shows he ype o su ace ha co esponds wi h a su ace c ea ed by DMLS echnology and does no show any signi ican ype o po osi y de ec . This ype o su ace can be seen in Figu e 5. This ype o AM echnology shows ha su ace s uc u e can con ain unmel ed pa icles o he me al powde . This ac also can be seen in Figu e 5. Ma e ials 2024, 17, x FOR PEER REVIEW 8 o 16 (a) (b) Figu e 5. (a) SEM image o specimen A (magni ica ion 500×); (b) de ailed ed ec angula a ea (mag- ni ica ion 1500×). (a) (b) Figu e 6. (a) SEM image o specimen B (magni ica ion 500×); (b) de ailed ed ec angula a ea (mag- ni ica ion 1500×). EDAX Analysis The seconda y ou pu eached by SEM imaging was he elemen al composi ion o he specimens. As can be seen in Table 3, he elemen al composi ion o specimen A quali a- i ely co esponds wi h ool s eel 1.2709, which is he ool s eel used o specimen A ab- ica ion. On he o he hand, Table 4. shows he elemen al composi ion o specimen B, which quali a i ely ma ches ool s eel 1.2344. This ype o ool s eel was used o specimen B ab ica ion. Table 3. EDAX analysis o specimen A. Elemen A omic Concen a ion [%] Weigh Concen a ion [%] C 31.65 11.01 O 20.08 9.31 Al 2.31 1.80 Si 2.09 1.70 Ca 2.50 2.90 Fe 29.63 47.95 Ni 10.23 21.12 Mo 1.51 4.20 Figu e 5. (a) SEM image o specimen A (magni ica ion 500 × ); (b) de ailed ed ec angula a ea (magni ica ion 1500×). Figu e 6shows he su ace o specimen B made by ADAM echnology. As can be seen, he su ace is apidly di e en in con as wi h specimen A. SEM images o specimen B do no show any ype o po osi y, which could lead o coolan media leakage in o he injec ion mold ca i y. The su ace s uc u e o specimen B shows ob ious signs o laye s. This is caused by ADAM echnology i sel . The p inciple o ADAM echnology is ha pa s a e p in ed om ilamen and hen sin e ed, and he p inciple is simila o FDM echnology. Ma e ials 2024, 17, x FOR PEER REVIEW 8 o 16 (a) (b) Figu e 5. (a) SEM image o specimen A (magni ica ion 500×); (b) de ailed ed ec angula a ea (mag- ni ica ion 1500×). (a) (b) Figu e 6. (a) SEM image o specimen B (magni ica ion 500×); (b) de ailed ed ec angula a ea (mag- ni ica ion 1500×). EDAX Analysis The seconda y ou pu eached by SEM imaging was he elemen al composi ion o he specimens. As can be seen in Table 3, he elemen al composi ion o specimen A quali a- i ely co esponds wi h ool s eel 1.2709, which is he ool s eel used o specimen A ab- ica ion. On he o he hand, Table 4. shows he elemen al composi ion o specimen B, which quali a i ely ma ches ool s eel 1.2344. This ype o ool s eel was used o specimen B ab ica ion. Table 3. EDAX analysis o specimen A. Elemen A omic Concen a ion [%] Weigh Concen a ion [%] C 31.65 11.01 O 20.08 9.31 Al 2.31 1.80 Si 2.09 1.70 Ca 2.50 2.90 Fe 29.63 47.95 Ni 10.23 21.12 Mo 1.51 4.20 Figu e 6. (a) SEM image o specimen B (magni ica ion 500 × ); (b) de ailed ed ec angula a ea (magni ica ion 1500×). Ma e ials 2024,17, 2477 8 o 15 EDAX Analysis The seconda y ou pu eached by SEM imaging was he elemen al composi ion o he specimens. As can be seen in Table 3, he elemen al composi ion o specimen A quali a i ely co esponds wi h ool s eel 1.2709, which is he ool s eel used o specimen A ab ica ion. On he o he hand, Table 4. shows he elemen al composi ion o specimen B, which quali a i ely ma ches ool s eel 1.2344. This ype o ool s eel was used o specimen B ab ica ion. Table 3. EDAX analysis o specimen A. Elemen A omic Concen a ion [%] Weigh Concen a ion [%] C 31.65 11.01 O 20.08 9.31 Al 2.31 1.80 Si 2.09 1.70 Ca 2.50 2.90 Fe 29.63 47.95 Ni 10.23 21.12 Mo 1.51 4.20 Table 4. EDAX analysis o specimen B. Elemen A omic Concen a ion [%] Weigh Concen a ion [%] C 10.69 5.39 O 41.33 27.77 Al 36.95 41.86 V 2.19 4.70 C 2.74 5.99 Fe 6.09 14.29 3.3. Cooling Sys em Flow Analysis Coolan p essu e, Reynolds numbe , and s eamline o al eloci y a e he pa ame e s ha we e e alua ed. The su ace oughness o he cooling channel in luences all hese pa ame e s men ioned abo e. The isualiza ion o he men ioned pa ame e s is shown in he igu es below, and alues o e e y pa ame e o each Rz pa ame e a e summa ized in Tables 5and 6. Table 5. Analysis esul s summa y o DMLS echnology. Rz [µm] P essu e [MPa] Reynolds n . [-] Flow Veloci y [cm/s] 21 0.433 95,930 605.3 18.9 0.425 95,980 605.6 16.8 0.418 96,060 606.6 14.7 0.413 96,110 610.9 12.6 0.407 96,190 616.7 10.5 0.400 96,260 626.6 8.4 0.393 96,320 630.9 6.3 0.386 96,360 637.1 4.2 0.379 96,390 640.0 2.1 0.371 96,410 642.0 As can be seen in Figu e 7, he maximal alue o he coolan p essu e is 0.481 MPa o Rz = 34 µ m. This alue dec eases wi h he channel leng h om he inle o he ou le o he cooling ci cui . This maximal p essu e alue in he cooling channel de ines he minimal pe o mance o he cooling uni . Such a high su ace oughness o he channels c ea es low esis ance o he coolan media, and he p essu e is hen highe . Ma e ials 2024,17, 2477 9 o 15 Table 6. Analysis esul s summa y o ADAM echnology. Rz [µm] P essu e [MPa] Reynolds n . [-] Flow Veloci y [cm/s] 34 0.481 95,810 601.2 30.6 0.476 95,860 601.3 27.2 0.465 95,890 602.5 23.8 0.456 95,910 603.8 20.4 0.439 95,940 605.8 17 0.420 96,050 608.3 13.6 0.410 96,130 614.4 10.2 0.398 96,270 626.2 6.8 0.389 96,330 636.5 3.4 0.378 96,370 640.4 Ma e ials 2024, 17, x FOR PEER REVIEW 9 o 16 Table 4. EDAX analysis o specimen B. Elemen A omic Concen a ion [%] Weigh Concen a ion [%] C 10.69 5.39 O 41.33 27.77 Al 36.95 41.86 V 2.19 4.70 C 2.74 5.99 Fe 6.09 14.29 3.3. Cooling Sys em Flow Analysis Coolan p essu e, Reynolds numbe , and s eamline o al eloci y a e he pa ame e s ha we e e alua ed. The su ace oughness o he cooling channel in luences all hese pa- ame e s men ioned abo e. The isualiza ion o he men ioned pa ame e s is shown in he igu es below, and alues o e e y pa ame e o each Rz pa ame e a e summa ized in Tables 5 and 6. As can be seen in Figu e 7, he maximal alue o he coolan p essu e is 0.481 MPa o Rz = 34 µm. This alue dec eases wi h he channel leng h om he inle o he ou le o he cooling ci cui . This maximal p essu e alue in he cooling channel de ines he min- imal pe o mance o he cooling uni . Such a high su ace oughness o he channels c e- a es low esis ance o he coolan media, and he p essu e is hen highe . (a) (b) Figu e 7. Visual coolan p essu e in e p e a ion: (a) DMLS echnology (Rz = 21 µm); (b) ADAM echnology (Rz = 34 µm). Figu e 8 shows he Reynolds numbe h oughou he channel leng h. The maximum alue in he case o Rz 34 µm is 119.43 × 103, and he a e age alue o he Reynolds n . is 95 810. As can be seen, mos o he channel is co e ed by yellow colo , which ma ches wi h an a e age alue. Figu e 7. Visual coolan p essu e in e p e a ion: (a) DMLS echnology (Rz = 21 µ m); (b) ADAM echnology (Rz = 34 µm). Figu e 8shows he Reynolds numbe h oughou he channel leng h. The maximum alue in he case o Rz 34 µ m is 119.43 × 10 3 , and he a e age alue o he Reynolds n . is 95,810. As can be seen, mos o he channel is co e ed by yellow colo , which ma ches wi h an a e age alue. Flow eloci y s eamlines a e shown in Figu e 9 o he oughness pa ame e Rz = 34 µm and Rz = 21 µ m. I is ob ious ha he maximal alue o low eloci y is in he co ne s o he cooling channel and is equal o 1226.33 cm/s in he case o Rz = 34 µm. Table 5summa izes he compu ed da a o all pa ame e s men ioned abo e. The maximal alue o he Rz pa ame e o DMLS echnology is 21 µ m and he minimal alue o Rz is 2.1 µ m, which is a alue ob ained by simula ing he cooling channel inishing p ocess, and his alue is commonly eachable by con en ional d illing. Coolan p essu e dec eases by lowe ing Rz. On he o he hand, Reynolds n . and low eloci y inc ease when Rz dec eases. Table 6summa izes he compu ed da a o all pa ame e s men ioned abo e. The maximal alue o he Rz pa ame e is sligh ly highe o ADAM echnology han DMLS. The minimal alue o Rz is 90% lowe han he maximal alue. Howe e , coolan p essu e has a dec easing pa e n om he highes o he lowes Rz. Flow eloci y and Reynolds n . g ow wi h dec easing Rz.