Shoe Quality Inspections: How to inspect shoe PQC
Quality is a very important feature of any pair of shoes you might make, buy or sell.
Knowing how to run a shoe quality inspection is a critical skill for shoe designers, developers and product line managers. When a new sample arrives it critical to inspect the materials, assembly technique and workmanship. Inspecting a shoe is a great skill to have as a shoe buying customer in a store. So here is how to grade and inspect a shoe like a professional!
Definition of Shoe inspection quality “A”, “B”, “C” – Grades
Are shoes with no functional defects or cosmetic defects that will impair the marketability of the shoe. These are high quality shoes, they look good and fit correctly. An A grade must follow the production specifications and match the approved confirmation sample.
Are shoes that have no major functional defects that will not cause injury to the person wearing the shoes. These shoes may have cosmetic defects, or production mistakes or workmanship issues that cannot be properly repaired. These will be discounted and or diverted to markets more tolerant of cosmetic defects.
Have major functional defects that could cause injury to the wearer or major cosmetic defects that cannot be repaired. Shoes are also considered C-grade if they have poor workmanship or materials defects that could shorten the normal life expectancy of the shoe, or damage the company’s reputation. These shoes should be destroyed.
How to inspect a shoe:
The main points in an inspection are as follows.
1. Is this the correct shoe, a matched pair?
2. Is the shoe clean?
3. Does the shoe follow the specification?
4. Is the workmanship high quality?
5. Is the shoe damaged in any way?
Let’s Inspect a shoe!
The first step in any inspection is to review the shoe packaging.
Is the shoe in the correct inner box for this model?
Is the box presentable? Make sure the box is not damaged or dirty.
Is the box the correct size? The shoe should not be crushed inside a small box.
Confirm the information on the box end label matches the shoe Color/Model/Size.
Check any hang tags to make sure they are correct for the shoe.
Remove the shoes from the packing box.
Do you have a left and right?
Are the shoe the same size & color?
Check the shoe tongue label information.
PQC know this sounds crazy but in the factory it’s not hard to put a right Size 7 and a left 7.5 into the same box.
Holding the shoe place the shoes bottom to bottom.
PQC are checking for symmetry. Does the pair really match in length. The size marks match but are the really the same length.
Now holding the shoe from the bottom roll the upper together side by side.
You are now checking the alignment of the shoe parts. Starting from the front roll the shoes to align the parts, toe caps, vamps, overlays, eye stays, eyelets.
While you have the uppers side by side compare finish and colors of each part.
Next hold the shoes up looking at the heels. Make sure the shoes sits on the outsole straight. Check that the upper is not rotated off center. Now rolling the the heels together you can check the Back height and collar lines match.
Next study the shoe bottoms, Do they match? Are the color blocks in the same location? Look over the midsole sidewall for wrinkles. Check the seam joining the upper to the outsole. We are looking for extra glue on the upper. 2mm is the limit for “over gluing” also look for over buffing of the upper.
On the shoe bottom check for color bleeding between color blocks. Lock of any paint covering mistakes. Check to make sure the outsole parts fit together neatly with no extra glue.
A complete inspection means the shoe is checked inside and out. Now that we looked over the outside it’s time to dive in. Look inside the shoe opening. Is the lining clean with no wrinkles. Run your hand around the collar, feel for any lump, bumps or glue. For leather shoes be on the lookout for any lasting nails or staples. For sport shoes make sure the footbed is straight, level and fitting correctly. Too small the footbed will more slide around, too big the footbed will be wrinkled or curled.
Next inspect the tongue lining for wrinkles and lumps. Run your hand down inside to check the vamp and toe cap from inside. Feel around the toe along footbed for lasting wrinkles. Feel for any rough stitching inside.
Finally make a quick check of the laces. Too long is usually not a big problem, too short will have to be fixed!
By this system we normally check pair by pair for satisfaction our value customer.
Common Shoe Quality Problems
When inspecting a shoe here are the common things you should be looking for.
Is the shoe clean? (White shoes can be hard to make in dirty factory.)
Color matching of shoe parts (suede and natural leathers can be tricky)
Material quality? hairy suede.
Rough trimming or Rough cutting
Upper wrinkles Check around the collar foam
Pressing parts on the Vamp
Crooked stitch lines
Dirty or smeared logo prints
Broken stitches or stitch holes with no stitches
Open seams – You can see threads like teeth this is called “grinning”
Over lasting can pull seams near the toe apart or cause wrinkles
Rubber blooming- white film on rubber parts
Rubber color bleeding
Tongues crooked or attached at different heights
Wrinkles on foam parts
Over glueing – Glue more than 2mm above the outsole edge
Over buffing – Buffing more than 2mm above the outsole edge
Under glueing- Dry spots along the sole with no glue
Outsole Parts splitting
Outsole cupped, bowed or crooked
SOME ESSENTIAL QUALITY ASSURANCE CHECKS AND TEST
1. SIZE MEASUREMENTS CHECK
Checking footwear dimensions typically involves measuring back height, quarter lateral height, medial quarter height, external toe cap length, and shoe length from heel to toe. Inspectors also measure the lengths of shoes laces, if any, and the dimensions of the shoe box against specifications.
2. NEEDLE DETECTION TEST
Like toys and many other goods manufactured in a factory, shoes need to be checked for needles and any other metal objects that might be hazardous to the consumer. Testing for needles is generally done by use of a machine that uses magnets to detect metal objects in the product. Such a machine should always be used at the factory that produces the shoes prior to shipment. One needle found in a single shoe of a unit sample is cause for rejecting an entire order.
3. FLEX/TORSION TEST
Footwear should be flexible and shoe flexibility is particularly a concern for those purchasing running shoes. One should be able to twist, bend or otherwise contort a shoe to a certain extent with relatively little effort and without damaging the shoe. To conduct a flex, or torsion test, grip a shoe from the heel end and toe end and bend the shoe upward into itself, then twist the shoe slightly to simulate torque. Check for any gaps in the bond used to assemble the shoe. Are there any cracks or damage? These are a signs that shoe adhesive strength may be questionable.
4. STITCH DENSITY CHECK
Stitch count is an important measure of quality and strength in textiles and, therefore, in many types of shoes that use fabric during their production. Visually count the number of stitches per inch of fabric on a shoe to determine quality. As a general rule, an adult shoe should have at least8-10 stitches per inch, while a child’s shoe should have 10-12 stitches per inch for added strength.
5. FRICTION TEST
Certain shoes require more grip for friction than others. That’s why it would be difficult to play basketball with shoes that have a smooth bottom surface. One can perform a simple friction test of footwear by setting a shoe on a flat surface and, without applying any pressure, gently attempting to slide the shoe across. If the shoe easily slides without much resistance, this is a very telling sign of a shoe’s applications and limitations. For more detailed test results, a lab can determine the dynamic coefficient of friction between footwear and flooring under various conditions.
6. ROCKING TEST
This test, normally used for inspecting high-heeled shoes, can be conducted as simply as tapping the back of the shoe to see if it rocks. Typically, if the shoe rocks more than 2mm in one direction or the other, the shoe isunstable and may be hazardous to the wearer.
7. BONDING TESTS
Bonding tests are used to determine the ability of an adhesive to maintain its integrity under a certain degree of stress. In the case of footwear, bonding tests can be used to determine adhesive strength between upper and midsole as well as midsole and outsole of a shoe. Special bond test equipment would be needed to measure specific adhesive strengths, which a factory may or may not have.
8. RUB TEST
A rub test consists of checking the color fastness of any fabric by rubbing the outside of the shoe with a dry or wet cloth. Similar to a crocking test used in testing fabrics, a rub test ensures that color will not bleed off from the shoe over time.
9. MARKING TESTS
Marking tests assess if a shoe is non-marking. One way is to turn the shoe with the sole facing upward and attempt to press a fingernail into the sole. If the sole dents or yields then it is a soft shoe and non-marking. A second test involves rubbing the shoe against or drawing a line with the heel of the shoe on a sheet of white paper with just enough force as not to tear the paper. If a mark is left on the paper, the shoe is not non-marking and fails the test. A shoe that fails marking tests is one that will likely leave scuff marks on hard floors.