What is Tolerance?
Tolerance is the ‘permissible limit of variation’. This is the amount of variation you could consider acceptable for quality standards. Every production environment will have their own tolerances set in place.
Textiles require a degree of leeway due to their malleable nature. Once garments are on a persons body, these small variations tend not to be noticeable. They tend to be indistinguishable against the wearer’s own asymmetrical qualities.
Why Tolerance is Necessary
The level of tolerance and necessity for it will vary from industry to industry. For many industries quality control will relate purely to customer satisfaction. For others industries, it may relate to the safety of the user. A low level of tolerance would seem preferable for consistency (regardless of industry). However, having stricter controls in place come with their own costs.
Environmental Impact
Waste is something we take very seriously. If the tolerance for production is too strict, this increases the number of ‘reject’ products. Flaws that are unnoticeable to most people, may cause perfectly acceptable products to be discarded. Some industries are raising their tolerance for this reason. For example, supermarkets are reducing food waste by accepting wonkier vegetables.
Note: Even where genuine faults do arise, we ensure these items are re-used for test printing or other purposes around our workshop.
Cost Impact
We’ve established that if a tolerance is too strict, the number of rejected products will increase. These unit losses increase both the cost and time of producing that product. You could argue reputation for being ‘reliably high in quality’ could potentially result in more orders. However, this would still require a balance (cost of rejects vs increase in orders) and is by no means guaranteed.
A higher yield from accepting a higher tolerance allows prices to be lower.
When Low/Zero Tolerance Is Important
There are companies who manufacture ‘critical’ parts, like those found in aircraft or medical devices. Their engineering tolerance has to be very low for safety (and liability) reasons. Companies who make other complex products and devices will also have low tolerance. Too much variation within their parts could render a whole product to be nonfunctional or unfit for purpose. This could actually lead to more waste than if the tolerance had been stricter.
Tolerance in Textile Construction
For textile manufacturers, there will be a tolerance for measurements when cutting the pieces used for assembly. No two garments are likely to be identical – even if they’re the same product and size.
Construction Process
Each textile factory will have its own quality control rules/tolerances to follow. Fabrics are highly malleable, which means it is easy to influence their shape. During production, these fabrics will require handling by both humans and machines. This leads to varying and unpredictable results when cutting and assembling garments. The chances of two garments being identical are incredibly slim. However, the manufacturer would consider them both to be acceptable – if they’re within the tolerance range.
Journey to Your Printer
When it comes to most manufacturing, especially textiles, these are often produced in countries all over the world. These products then have to do some serious air miles to reach distributors. The distributors will then sell the products to printers (us) for customising. For us as printers to set a higher tolerance for what we receive than the manufacturer themselves and reject a product (that is not considered defective) at this stage, would be incredibly wasteful. Therefore we do not accept responsibility for garments that are not considered defective.
Perceivable Variation
As mentioned earlier, when wearing a garment, variations within the tolerant range are not noticeable. The fabric will contort and mold to a person’s a-symmetrical body shape, posture and movements. End user customers are also unlikely to intentionally compare products directly (except for the purpose of checking if they’re different).
If you do feel it’s important for there to be minimum variation for your brand, it’s a good idea to check with the garment manufacturer what their tolerances are.
Tolerance in Textile Printing
Print Positioning Tolerance
We will always try to meet specific measurements for positioning and consider our accuracy to be some of the best in our industry. However, we can still only treat these specifications as guidance. We allow for a discrepancy of up to 2cm from the target distance. We do not consider variations less than this to be misprints.
Loading Accuracy
When we screen print at Blackwater Studios, all garments are all loaded onto carousel pallets by hand. We mark the desired position and aim to hit this target each time we load a t shirt. Since we load a new t shirt every few seconds, fine-tuning the position down to the millimeter isn’t feasible. This would require stopping production and greatly increase the length of each print run. This would increase both the cost of each job and also the turnaround time required. Therefore, this is one factor for some position variation.
Construction in Relation to Positioning
Garment construction also naturally factors into the positioning. When a single batch of the same size and style of t shirt may have variation within the cuts themselves, this will alter the ‘relative’ positioning of the print.
For example, consider a print that must be horizontally central. There are multiple possible reference points for doing this. You could use the sleeves as a guide to the center of the chest, rather than the neck hole. However, if the neck hole has been stitched with uneven space between the shoulders, the print won’t be central to the neck. It would either be out of line with the neck, or closer to one sleeve.
Combining both manufacturer tolerances and printing processes makes it very difficult to reliably hit the same target each time. However, ‘perceivable variation’ (see Tolerance in Textile Construction) also applies to positioning. We feel our tolerance specifications consider this fairly.
Genuine Defects
Having a range of tolerance doesn’t mean quality control isn’t important. If we receive and/or spot a garment that we consider to be defective, we will remove this from the batch. Example defects include holes or misprints (see Misprints/Shortages in our terms). We will replace defective items if stock availability and time constraints allow. We will keep defective garments for test printing on, to ensure they get as much practical usage as possible.
If you have received an item you consider to be defective, please let us know.