More and more frequently, plastic resin producers are turning to product defect removal services instead of simply downgrading their bad production and selling on the second quality market at a loss. When done properly, it can make the difference in keeping happy customers, increasing margins and relieving burdened plant production schedules.

What Are Product Defects? 

Resin made that does not fit the customer’s specifications. Some defects are formula related:

  • Melt index 
  • Gels
  • Additive concentration

Others are contaminates:

  • Metal (embedded and loose)
  • Black specks
  • Discoloration
  • Moisture (embedded and surface)
  • Agglomerates
  • Fines/streamers

Defect removal services focus on removing contaminates. Equipment and processes have advanced so that can be removed bringing sub-prime resin back to prime. 

Is Defect Removal Worth It?

No one plans to make defective material but it happens to every producer and most have systems in place to sell to companies on the second quality market at a greatly reduced price. Though this is typically the “easiest” thing to do, it is usually not the most economical. When prime resin is downgraded it receives a fraction of its value.

For example: your prime resin price is $2.00/lb. and once downgraded its value is reduced 75%. On 100,000 pounds you have reduced your revenue from $200,000 to $50,000 for that batch.

Downgrading products also often cause shipping delays to customers and costly plant rework.

What Does Defect Removal Cost?

Service price vary from providers and the type of defect will also impact the cost of these services. A good rule of thumb for budgetary consideration is typically $0.10/lb. There can be other cost as well including transportation, handling and storage that also vary between providers.

Should You Consider Defect Removal?

Some of the questions that should be answered when vetting the idea are:

Is the value of my prime resin enough to warrant cleaning?

It is usually not economical to consider defect removal for commodity plastics. Usually specialty resins (higher price material) are more likely candidates.

Does the delta between my prime price and downgraded price warrant cleaning?

If the delta is minimal, it may not be worth the extra steps and logistics management to consider cleaning.

Where will my products be cleaned?

Geography can be a huge factor in making this decision. Ideally the service provider is local to production or on the way to the end user.

How do I qualify the service provider?

Take the time you need to get your questions answered regarding the quality of service. Be specific on the removal specifications you have.

What Are the Options for Defect Removal?

Options depend on the type of defects you are challenged with:

Product Size

Product size issues are typically addressed through screening technology. It’s important to learn how the provider manages differing particulate sizes to get the maxim separation with the least amount of loss in a single pass.

Discoloration

Discoloration or embedded contaminates are usually removed through optical sorting. Most of this is done through contrast. The equipment looks for pellets that do not look like all the others and removes. Important questions for the service provider could be: 

  • Yield/loss ratio (good product lost in separation)
  • Throughput
  • Number of passes (cost increase)
  • Equipment cleaning processes.
  • Sample and inspection processes.
  • Calibration and maintenance processes.

Metal contamination can be addressed though electrical magnetic detection and removal systems, rare earth magnets or if embedded, optical sorting.

Moisture Removal

Internal/External moisture removal is typically accomplished through residence time in hoppers while desiccant dried air as passed through the resin. Dwell time varies depending on concentration level and product characteristics. Heat can also be used to expedite the process though must be tightly controlled as heat can alter the resin properties.

The Bottom Line

Defect removal is becoming more popular as a means to increase margins, relieve production rework and meet today’s high quality standards. Although downgrading can be faster and easier, for specialty resins it is almost never the most economical. In our experience, cleaning unplanned defected product is not a cost but a positive impact to the producer’s bottom line. 

Increase Your Performance with Clean Resin

Plantgistix can help clean your resin and maintain your profitability. Ask us how.

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