04Lecture-Calc - Manufacturing Production Processes ENGR3190U Lecture 04 Chapter 13 13.2.2 Analysis of Extrusion Calculations For Plastics What is

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 13 - 13.2.2 Analysis of Extrusion Calculations For Plastics What is the flow rate of polymer melt in extruder? Refer to Figure 13.5 in textbook As screw rotates inside barrel, the melt is forced to move forward towards die, this is drag flow . A w A D d A DN Q f c d cos ) tan ( ) cos ( 5 . 0 - = π Q d = volume drag flow rate (m 3 /s) D = screw diameter (m) N = screw rotational speed (rev/s) d c = screw channel depth (m) A = flight angle = D p A = tan where p = pitch w f = flight land width (m) If we assume flight land width is negligibly small then formula simplifies to A A Nd D Q c d cos sin 5 . 0 2 2 = Compressing the melt through downstream die creates back pressure flow . = dl dp A Dd Q c b η 12 sin 2 3 Q b = back pressure flow (m 3 /s) η = viscosity (N-s/m 2 ) 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
dp/dl = the pressure gradient (Mpa/m) – stronger at die end, weaker at hopper end. (Figure 13.6) If we approximate dp/dl by straight line then formula simplifies to
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/09/2010 for the course MECH ENG mech301 taught by Professor Yang during the Spring '10 term at UOIT.

Page1 / 4

04Lecture-Calc - Manufacturing Production Processes ENGR3190U Lecture 04 Chapter 13 13.2.2 Analysis of Extrusion Calculations For Plastics What is

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online