Sustainable machining strategies of Al-alloys

Abstract

Background. Industries are facing increasing pressure to adapt to sustainability
regulations being put in place. This forces industries to rethink traditional manufac-
turing operations and find ways to make them more sustainable. In the traditional
industries there are a lot of coolants being used, these have a big impact on both
the environment sustainability as well as social sustainability. Two production meth-
ods show substantial improvement compared to traditional flood coolant, videlicet
dry and MQL. These have the potential to drastically reduce waste and disposal of
hazards material and overall reduce the carbon footprint.

Objectives The objective of thesis is to compare and asses the machinability per-
formance of three production methods through force and surface roughness compar-
isons. To understand if the production methods are sustainable and a future option
the materials will be compared in terms of forces and surface quality.

Methods The experiments were divided into two sections as it made it easier to
compare, first there is on section comparing all materials against each other in dry
conditions. Second section compares Wrought aluminum in both dry and MQL con-
ditions to understand the influence of MQL against dry. The samples were prepared
for machining by removing defects on the surface to minimize any disturbances in the
force readings. After that the samples were machined in five different cutting speeds
ranging from 1200 m/min to 2000 m/min, during machining at a constant cutting
speed and eight different feeds to see the implication of various cutting feeds. With
all the data gathered using a Kistler force sensor, where the signal was processed
using a Matlab script developed by the author.
Results The results provides insight into the machining operation and where the
potential pitfalls when machining tends to be. They also provide insight into the more
favorable settings to optimize production to either increase production or sustain tool life with optimal surface roughness.

Conclusions There is a slight relation that can be observed between cutting speed
and feeds effect on surface roughness. Interestingly there seems to be better per-
formance both in terms of forces and surface roughness when machining Rheo cast
Aluminum, but Wrought Aluminum beats them both. It is not easy to predict which
insert will perform better but in some cases CC beats PCD and vise versa. Even with
knowledge of the material composition it is not easy to predict the machinability. In
general MQL seams to perform better compared to dry cutting conditions, but in
terms of surface roughness there is a glimpse that dry could outperform MQL in the
future.

Abstract (Swedish)

Bakgrund. Industrierna utsätts för allt större press att anpassa sig till de håll-
barhetsregler som införs. Detta tvingar industrierna att utmana de traditionella
tillverkningsprocesser och hitta sätt att göra dem mer hållbara. I de traditionella industrierna används mycket kylvätska, som har stor inverkan på både den miljön och
den sociala hållbarheten. Två produktionsmetoder uppvisar betydande förbättringar
jämfört med traditionell kylvätska, därbland torr och MQL. Dessa har potential att
drastiskt minska avfallsminskningen av material och farliga ämnen samt totalt sett
minska koldioxidavtrycket.

Syfte. Syftet med detta examensarbete är att jämföra och bedöma bearbetbarheten
hos tre material som har olika värmebehandlingar. För att förstå om produktions-
metoderna är hållbara och ett framtida alternativ kommer materialen att jämföras
med avseende på skär krafter och ytkvalitet.

Metod. Experimenten delades in i två sektioner eftersom för att underlätta jäm-
förelsen, först finns det en sektion som jämför alla material mot varandra under
torra skär förhållanden. I det andra avsnittet jämförs smides aluminium i både torra
och MQL-förhållanden för att förstå påverkan av MQL jämt emot torra. Proverna
förbereddes för bearbetning genom att avlägsna defekter på ytan för att minimera
eventuella störningar i kraftavläsningarna. Därefter bearbetades proverna i fem olika
hastigheter från 1200 m/min till 2000 m/min, under bearbetning med en konstant
skärhastighet var det åtta olika matningar för att se innebörden av olika skärmat-
ningar. Alla data samlades in med hjälp av en Kistler där det sedan bearbetades
med hjälp av ett Matlab-skript som utvecklats av författaren.

Resultat. Resultaten ger insikt i bearbetningsoperationen och var de potentiella
fallgroparna vid bearbetning tenderar att finnas. De ger också insikt i de mer
gynnsamma inställningarna för att optimera produktionen för att antingen öka pro-
duktionen eller bibehålla verktygslivslängden med optimal ytjämnhet.

Slutsatser. Det finns ett litet samband mellan skärhastighetens och matningarnas
effekt på ytjämnheten. Intressant nog verkar det finnas bättre prestanda både när
det gäller krafter och ytjämnhet vid bearbetning av Rheo-gjuten aluminium, men
smidesaluminium slår dem båda. Det är inte lätt att förutse vilket skär som kommer
att prestera bättre, men i vissa fall slår CC, PCD och vice versa. Även med kunskap
om materialets sammansättning är det inte lätt att förutsäga bearbetbarheten. I
allmänhet verkar MQL prestera bättre jämfört med torra skärförhållanden, men när
det gäller ytjämnhet finns det en antydan om att torra skärförhållanden kan överträffa
MQL i framtiden

Popular Abstract

As industriers are facing increasing pressure to adapt to sustainability regulations, it challenges industries to rethink traditional manufacturing. Within traditional metal cutting industries they rely heavily on coolant to reduce wear and chip evacuation among other things. The problem with flood coolant is that the once used are used in large quantities and are hard to recycle, which has a big impact on both environmental and social sustainability as particles can reach operators or make the floor slippery. To reduce/eliminate the use of flood coolant two promising production methods named MQL (Minimum Quantity Lubrication) and Dry machining have shown great potential.
The objective of the thesis is to compare and evaluate the performance of three common production methods against each other when machined in two different cutting conditions (MQL and Dry). They were evaluated in terms of measured cutting forces and surface roughness. The result would allow for further assessment of machinability and sustainability.

The experiments conducted during the thesis were divided into section. The first one compared two production methods agains each other, HPDC (High Pressure Die Casting) and Rheo casting (Similar to HPDC without high pressure) in dry cutting conditions. The second comparison was made between MQL and dry cuttign condition using the same material as a constant. Through the experiment there were a change of cutting speeds and feed rate as well as different cutting tool materials. This was to get a wide spectrum of potential industrial applications and data to evaluate performance.
The results provided insight into where the machining operation had tendencies to perform optimally and also where it might lack in performance. This can be a useful insight for production purposes to identify optimal cutting conditions.
What could be concluded form the experiments was that using the data it is possible to identify optimal cutting conditions during machining for both Rheo casting and HPDC. It also allowed for a good representation of how well dry cutting conditions perform in comparison to MQL which has been proven to compete with flood coolant. Even though dry gave good results it needs to be stated that tool wear was not evaluated. Rheo casting being a more sustainable variant of HPDC gave results which indicates that Rheo casting could definitely replace HPDC in terms of machinability for future productions.

• author: Lövgren, Lucas
• supervisor: Volodymyr Bushlya
• organization: Production and Materials Engineering
• course: MMTM05 20241
• year: 2024
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Milling, Dry, MQL, Aluminum.
• report number: CODEN:LUTMDN/(TMMV-5370)/1-65/2024
• language: English
• id: 9170333
• date added to LUP: 2024-07-09 15:01:02
• date last changed: 2024-07-09 15:01:02