Tag: testing

Coordinate measurement machines (CMM): What are they and who needs it?

Within our testing laboratory in Ningbo, China, our engineers perform mechanical, electrical, environmental and other special testing as required by our clients. Experienced engineers use applicable and regionally specific standards, such as ASTM, IEC or ANSI specifications, to conduct a variety of in-house and on-site testing. One of our most common testing procedures involves the use of either a portable or in-house CMM.  

What is a coordinate measurement machine? 

“A coordinate measuring machine (CMM) is a device for measuring the physical geometrical characteristics of an object.” 

“Dimensional inspection is used in process control; its results adjust the parameters of
the manufacturing process to achieve the desired outputs. Computer controlled
dimensional inspection is typically performed with a Coordinate Measuring Machine
or CMM, which is a very precise mechanical system designed to move a measuring
probe to determine coordinates of points on a work piece surface. A CMM consists
of a workspace in which parts are fixed, a sensor for detecting the part surfaces, a
mechanical assembly for moving the part sensor around the workspace, and a
computer with software used in calculating the part dimensions based on the sensor
measurements.” (Source)

Quality testing adventure… Evaluating strollers

They say you should walk 10,000 steps per day, and our engineers in China are hitting the mark as they road test these strollers through various road conditions.

Sebastian Oarcea, Pro QC’s Chief Engineer, explains the evaluation in more detail below.

Purpose:  To determine the functionality and performance of the strollers in a real-life operating condition.

Process:  One sample is subject of functional evaluation in reference with instructions manual provided and applicable standard prior to road test to identify potential failure modes.

The road test is performed with strollers loaded at maximum stated by manufacturer (both for occupant and luggage compartments, basket etc.) over terrain that mirrors the expected usage environment (including stairs, inclined road, grass and sand roads etc.).

The strollers are tested in ways that would parallel the way it would operate in normal home use.  Normally 5 samples of each model are included in this test.

Report: The final Summary Report evaluates and records the performance and physical aspects of the stroller during the test. It includes initial observations from the receiving of the product, packaging, compulsory markings and warnings, instructional literature, Mean Time To Failure (MTTF) with reliability data in hours of use and distance, comments (both positive and negative) and suggestions from testers, satisfaction score and daily reports. The test distance is about 50 km (for current road track 53km).

Product_Testing_Strollers

Inspecting textiles & garments

In our latest newsletter, we’re talking about inspecting textiles and garments and the specialized expertise required for this industry. Unlike wood, metal and other materials, textiles and garments have unique variables that may result in unexpected issues throughout manufacturing and during the final inspection. As one of Pro QC’s textile inspectors noted, “it’s an art of using many variables to produce a piece of art.” A garment or fabric inspector must bear in mind these variables and conditions that can result in defects and delayed shipments.

Irene Gebrael, an inspector for Pro QC in the New York and New Jersey area, indicates the importance of an inspector’s specialization in this field is based on the following two considerations:

1) Credibility & Process Knowledge 

In fabrication, there are many defects that are caused by variables that may be due to ginning, spinning, finishing, dyeing, or might be due to a mistake in checking. To stand on the reason of the defect, an inspector must have prior knowledge of the processes for dyeing, finishing (fabrication), cutting, sewing (garment manufacturing), standards for care labels and regulatory compliances.

2) Inspection Conditions 

The factors causing confusion and misinterpretation of defects are numerous, so an inspector must have a solid understanding of the conditions for inspection, such as the lighting, the effect of rolling on fabrics, the effect of packaging on garments, etc. For example, some of the common problems that differentiate textiles from other products are shade and the effect of light on shades during inspection. Inspectors must identify and use a good source of light to discover shade issues such as un-leveling and shade continuity.

Common defects noted during textile and/or garment inspections include:

-Defects in appearance, such as marks, fraying fabric or unfinished edges, etc.

-Defects with seams and stitching, including open seams, incorrect thread selection, skipped stitches, etc.

-Defects concerning color, such as dye spots and color fastness

-Defects concerning fabric, such as its material, fabric weight, cuts or tears, slubs or misweaves, etc.

-Defects concerning sizing, labeling and packaging, such as labels missing or top/bottom sizes are mismatched

-Defects concerning care label information, content label information, hang tag descriptions, correctness of components or trims, zip teeth smoothness, etc.

-Defects concerning measurement and fit

-Defects concerning safety, such as pins, needles and staples not being removed

Applicable standards are used, such as those listed below:

ASTM 5430-07 (Standard Test Methods for
Visually Inspecting and Grading Fabrics)

These test methods describe a procedure to establish a numerical designation for grading of fabrics from a visual inspection.

ASTM D3990-2012 (Standard Terminology Relating to Fabric Defects)

This terminology covers defects in both woven and knit fabrics.

ASTM D3775 (Standard Test Method for
Warp End Count and Filling Pick Count of Woven Fabric)

ASTM D3136 – 04(2008)e1: Standard Terminology Relating to Care Labeling for Apparel, Textile, Home Furnishing, and Leather Products 

This test method covers the measurement of warp end count and filling pick count and is applicable to all types of woven fabrics. The number of warp yarns (ends) per unit distance and filling yarns (picks) per unit distance are determined using suitable magnifying and counting devices or by raveling yarns from fabrics.

Evaluations, such as wash testing, can often be performed on-site.  For additional information regarding textile and garment inspections and/or testing, or to review example reports, contact us.

Hi-Pot Test – Abbreviated Demonstration Posted

We have edited the extended version of the recent high potential (hi-pot) demonstration video.  Comments and suggestions are always welcome and appreciated.  Additional videos are pending release…

http://www.youtube.com/watch?feature=player_profilepage&v=r44qEvOHkMQ