© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.

MECOP Experience Trent Smith 2nd Internship Mechanical Engineer, OSU

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 2

Laser welding development •  Goal: optimize laser welding process for assembly that will

guide decisions to increase weld strength and resistance to environmental stress cracking.

•  Variables: •  Line energy (laser power, speed, cycle time) •  Weld collapse and clamping force •  Material properties

•  Process: design experiments and collect data to create a model characterizing optimal weld parameters and guiding material selection decisions

•  Knowledge gained: DOEs, statistical modeling experience, plastic/polymer interactions, thermal-induced stresses, environmental stress cracking and resistance

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 3

Quantitative Stress Analysis Using Birefringence

•  Goal: characterize stress distribution in transparent molded parts •  Background:

•  When viewed in cross polar, stressed transparent materials display colored fringe patterns – termed birefringence

•  A calibrated wedge compensator can be used to calculate wavelength retardation which correlates to stress

•  Knowledge gained: alternative stress analysis techniques, designing for reduced residual mold stress, impact of laser welding on stresses and ESCR

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 4

Determining the Stress-Optical Coefficient

Coupon

Clamps Load Cell

Threaded rod

Load-inducing nut

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 5

Mold parameter optimization •  Characterizing and comparing residual mold

stresses allows for better mold specifications •  Analysis allows for quick comparison between

parts & processes as well as opportunity for quantitative data

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 6

Impact of Knit Lines and Cold Welds on Performance

Cold weld region (POI)

© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 7

Product Engineering •  Product engineers support the line and ensure that processes remain stable •  Responsibilities:

•  Yield tracking and improvements •  Contamination analysis and prevention •  Cycle time studies & reduction •  Gauge repeatability & reproducibility •  Design Support

•  Knowledge gained: tool validation, manufacturing processes and control, FTIR applications, manufacturing line team work