DESIGN OF NEW PRODUCTION PROCESSES FOR MESH COMPONENT

AIM

To improve the productivity of filter by changing the production processes and standardizing the existing practices of producing the mesh.

ABSTRACT

The product under consideration (filter ) undergoes various process which involve more time which intern reduce the productivity . This project is about reducing the number of process and improving productivity by reducing the cycle time.

Study of the existing process The filter component undergoes

following operation1. Cutting2. Blanking3. Forming 4. Trimming and Piercing5. Injection molding6. Finishing

Brief explanation of operations followed

Cutting : A large sheet of dimension 100*100 cm is cut into ribbons of 7*100 cm.

Blanking :The ribbons or then loaded into the blanking press and blanked to a diameter of 7cm.

Forming : The blanks are loaded in the forming press and fly press is operated to form the blank to required dimension. The punch is heated to deform the blank.

Trimming : The formed piece is then loaded in to the trimming press where chips are removed to get the required dimension of the mesh.

Injection molding: Mesh is loaded in to the injection molding machine. Here the filter is obtained with some flash .

Finishing : The chips are removed and filter is visually inspected.

Phases of production

FormingTrimmingInjection Molding

Mesh Material- Nylon 6

Mechanical Properties Tensile strength – 78 Mpa Shear strength – 55 Mpa

Material – POM TICONA M90

Polyoxymethylene (POM) : Polyoxymethylene (POM), also known

as acetal, polyacetal and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and sold variously by such names as Delrin, Celcon, Ramtal, Duracon, Kepital and Hostaform.

POM advantages: High abrasion resistance Low coefficient of friction High heat resistance Good electrical and dielectric properties Low water absorption

Properties of POM

Shear Strength (73°F)- 7920 to 8120psi Density – 1410 kg/m^3 Rockwell Hardness (73°F) - 80 to 83 Melting Temperature-329 to 331°F Thermal Conductivity(73°F)-1.6

Btu·in/hr/ft²/°F

Cycle time and productivity calculations of existing process

Operation Cycle time (sec)

Trial 1 Trial 2 Trial 3

Cutting(single RM sheet)

255 245 253

Blanking (single piece)

3 3.2 3.3

Forming (single piece )

15.7 16.5 15.5

Trimming (single piece)

6 5.5 6.2

Cycle time= Blanking time +Forming time +Trimming time

=3.1+16+5.8= 25 sec/piece

Performance Calculation Planned production time =No. of working hours – break time

=12-1= 11 hours = 39600 seconds Operating time = planned production time - down time

=39600-5400 = 34200 seconds Quality = good piece/number of pieces

=1790/1800 = 0.99444 Performance = ideal cycle time

operating time/no. of pieces

= 18

34200/1800

=0.94 Availability = Operating time / Planned production time

=0.86

Overall equipment efficiency = Availability*Performance*Quality

Overall equipment efficiency =0.804*100=80.4%

First Proposal :Special Purpose Machine

Die Forming punch

Trimming punch

New Design

Replacing all manual and mechanical machines with hydraulic machines and electrical and electronic devices.

Second proposal: Compound Die based SPM

Combining all the operations in to single operation using compound die based SPM.

Compound Die

Press Capacity Calculation:Press Capacity = press capacity for trimming

+ press capacity for piercing =𝞹*D*t*s+ 𝞹*d*t*s

t,Material thickness = 0.5 mmS, shear strength = 55 Mpad, diameter for piercing = 17.25 mmD, diameter for trimming = 36 mm

Press capacity =*0.5*e-3 *55*e6 *(0.036+0.01725) =4578 N= 467 kgf.

Drawing Force Calculation

Drawing Force = 𝞹*d*t*s*(D/d-k) Where,d- cup diameterD- Blank diametert- Thicknesss- Yield strengthk- Constant usually 0.6 to 0.7 =𝞹*31*0.5*78*(70/31-0.6) =651.11 KgFor safety multiplying with factor 1.25,Force = 800 Kgf

Spring calculation

Spring wire diameter, d = 3mmSpring diameter, D = 25mmAxial load, P = 800 KgfModulus of rigidity, G = 0.805563 Kgf/cm2

Number of turns, n = 10Pitch, P= 4mmSpring index, C=D/d=25/3=8.33Wahl stress factor, K= 1.15

Spring Calculation

Shear stress, S=K*8*P*D/(𝞹d2 ) =1.15*8*800*25/(𝞹*32 ) =260 Kgf/cm2Deflection Of Spring, y=8*P*C3* n /(G*d) =8*800*8.333*10/(0.805*3) Stiffness, q=G*d/(8C3 * n)

=