The regrind management injection molding teams need goes beyond recording kilograms in a bin. Before that material reaches a hopper, someone must know its exact grade, source, condition, and approved use. A bag marked “black regrind” leaves too much to guess.
This is where the ERP design matters. If the system treats every kilogram of ground material as usable stock, purchasing may delay an order that production still needs. If it records all collected scrap as disposal, it loses sight of material that could be recovered.
The practical goal is to connect collection, processing, approval, and reuse. This guide shows how to build those records, control blend ratios, and measure recovery without overstating available stock or savings. The examples cover thermoplastic recovery from identified production sources.
What scrap and regrind mean in production
Scrap includes rejected parts and other material removed from the intended production output. Regrind is material reduced in size by grinding or granulation for possible reuse. Turning scrap into regrind does not establish that it meets the requirements of the next molding job.
Keep four quantities visible: collected scrap, material sent for grinding, ground output, and output released for a specific use. The quantities can differ because of sorting, fines, material retained in equipment, and quality decisions. Their records should explain those differences.
Also keep the original rejection against its source job. Reusing its material does not undo the failed part or recover the production time already spent making it.
Start the ERP design meeting at the grinder
Before discussing dashboards, follow a labeled container from one press to the grinding area. Check who weighs it, who checks its contents, and who decides what happens next. Then follow the ground material into storage and back to a production order.
Can different jobs share a container? What happens when a label is missing? Does quality approve the material itself, its use in a particular part, or both? These decisions shape the database.
Write the answers into the workflow before configuring stock locations. An internal location called “Regrind Store” tells you where material sits. It does not, by itself, tell you whether a specific customer or product permits its use.
For an ERP project, make release authority explicit. Stores can confirm quantity and location. Quality or the designated technical approver should confirm suitability under the approved material and product rules. Test that separation in the proposed system.
Separate scrap while its identity is still clear
Collection is the cheapest place to preserve material identity. Once several grades enter one unlabeled container, accurate weighing cannot reconstruct their contents. Keep collection rules visible at the press and grinding area.
Use dedicated, labeled containers for approved material categories. Separate different grades, colors, and restricted sources unless a documented process permits combining them. “Same polymer” is too broad when grades have different fillers, additives, or customer approvals.
Treat purge, contaminated material, floor sweepings, and parts containing inserts as separate streams for evaluation or disposal. Do not send them into the normal regrind route merely because the grinder can accept their shape.
Put useful information on the container label
The label should identify the material grade, color, source production order, collection date, and container number. Link it to the resin lots used by the source job. Add net weight after removing the container tare.
For rejected parts, preserve the defect reason and source mold or cavity where known. Identify runners by their source job. Hold material with missing information until the team resolves the gap.
When approved sources are combined, create a new batch reference and retain every contributing source and quantity. A replacement label must not erase the history behind the new container.
Record grinding as a transformation
Grinding changes the form of the material, so it needs an input and output record. Moving 100 kg from “Scrap Area” to “Regrind Store” records a location change. It does not explain sorting losses, ground output, or the identity of the resulting batch.
Create separate item identities for virgin resin, recoverable scrap, and regrind where the workflow requires them. Use kilograms as the material stock unit. Track bags or containers as packaging references rather than assuming every container holds a fixed quantity.
Record the recovery order, input batches, net quantities, granulator, processing time, and output lot. Include the cleaning check required before a grade or color change. Link any retained material to the open recovery order so the next shift can account for it.
Conair’s granulating scrap guidance emphasizes clean, uniform granulate and matching equipment to the material and processing requirements. The ERP should preserve the relevant checks and results. It cannot replace the physical controls that keep material clean and consistent.
A worked example of physical stock and approved stock
Consider an illustrative recovery batch with 120 kg of collected material. Sorting excludes 15 kg, leaving 105 kg issued to the recovery operation. By the reporting cutoff, the operation produces 100 kg of regrind and 3 kg of fines, with 2 kg still unprocessed in the equipment.
Quality then releases 70 kg of the ground output for the intended product. Another 20 kg awaits a decision, while 10 kg is rejected after grinding. These figures are examples of workflow states, not recommended process yields.
| Position at the reporting cutoff | Quantity in kg | Recorded status |
| Regrind approved for the intended product | 70 | Released stock |
| Ground material awaiting a decision | 20 | Quality hold |
| Ground material rejected after processing | 10 | Disposal pending |
| Fines separated during processing | 3 | Separate disposition |
| Unprocessed material retained in equipment | 2 | Work in progress |
| Material excluded before grinding | 15 | Disposal pending |
| Total accounted for | 120 | Matches collected quantity |
The table shows mutually exclusive quantities. Do not add the 105 kg input or the 100 kg ground output again; those are earlier stages of the same material.
There is 100 kg of physical ground output, but only 70 kg is released for the intended use. Against the original 120 kg collection, immediate approved recovery is 70 ÷ 120 × 100, or about 58.3%. Held material could change that figure after a documented decision.
Where decisions differ within a recovery batch, identify separate containers or child lots for the released, held, and rejected portions. Keep all three linked to the source batch. Releasing 70 kg must not accidentally make the entire 100 kg available.
If a job needs 80 kg of approved regrind, this batch supplies only 70 kg at that cutoff. Planning must resolve the 10 kg gap through another approved batch, an authorized recipe change, or a revised schedule.
Define blend percentages before configuring recipes
“Use 20% regrind” is incomplete unless the percentage basis is clear. A percentage of total feed differs from a percentage added against virgin resin. Put the agreed basis in the recipe, operator instructions, and ERP validation.
For an illustrative two-material, 250 kg blend containing 20% regrind by total mass, use 50 kg of approved regrind and 200 kg of virgin resin. The calculation is 50 ÷ 250 × 100 = 20%.
Adding 20 kg of regrind to 100 kg of virgin gives a 120 kg blend. Regrind makes up 20 ÷ 120 × 100, or about 16.7% of total feed. That recipe is not a 20% regrind blend on a total-feed basis.
Where colorants or other additives form part of the blend, specify whether they are included in the denominator. Record actual quantities fed, including approved adjustments. A nominal bill of materials alone does not prove the blend used at the press.
Approve the ratio for the material and part
Do not apply one plant-wide limit simply because it is easy to configure. The permitted content depends on the material, application, customer requirements, and validated process. Some jobs may prohibit recovered material.
BASF’s Ultramid processing guidance discusses contamination, moisture, repeated processing, and application restrictions when considering reuse. These considerations support a material-specific approval process. They do not establish a universal blend percentage for every resin or part.
Maintain the permitted sources, ratio basis, maximum content, applicable part revision, required tests, and approving person. Give recipe changes a controlled revision. The system should prevent a superseded instruction from quietly becoming the next job’s recipe.
Preserve processing history when material is blended
Generation tracking becomes difficult when virgin resin and previously processed material share a molding run. Scrap from that run inherits a mixture of histories. Assigning the new recovery batch a single fresh number does not make that history disappear.
For example, imagine a job fed with 80 kg of virgin resin and 20 kg of approved regrind. Its runners come from that blend. They cannot accurately be labeled as scrap from virgin-only production.
Define what “generation” means in your procedure, such as previous molding passes. Keep the contributing feed lots and known histories linked to the recovery batch. Where a rule requires a maximum permitted history, use a documented method the technical team has approved.
If history cannot be established, mark it unknown and hold the batch from uses that require proof. An average generation value can conceal older material. Use it only if the relevant approval explicitly permits that method.
For continuous recovery beside a press, decide how you will define batches or traceable time windows. Record recipe changes, material transitions, retained material, and interruptions. If the required history cannot be demonstrated, use a separately controlled recovery route.
Make release depend on condition and intended use
A material approval should answer two questions: is this batch acceptable, and where may it be used? Store both answers. A batch suitable for one internal product may be unsuitable for another customer’s specified component.
Capture the inspection and test results required by the material and product procedure. These may include identity, contamination, particle condition, moisture, or relevant part performance. Follow the applicable supplier guidance when setting drying and processing conditions.
Record when material is opened, dried, released, and returned from production where those events affect its status. If exposure or handling exceeds the approved conditions, route it for the required review. A previous release should not automatically authorize every later use.
Separate storage locations can help operators, but test reservation controls as well. Try to allocate held regrind to a real production order. The test should show that the hold prevents use rather than simply displaying a warning beside otherwise available stock.
Connect regrind management with the ERP stock model
Odoo for manufacturing provides building blocks for this workflow. Its lot number documentation describes lot identification and tracking. Its by-product documentation describes recording additional manufacturing outputs through bills of materials.
Test the complete workflow in the proposed edition and version. Item identities, stock movements, approvals, and source relationships may need additional fields, controls, reports, or integration.
For a Manufacturing ERP implementation, trace one batch through collection, grinding, release, blending, and finished output. Retrieve its sources, destination jobs, and quantities at every stage.
Pay attention to how rejected parts become recoverable input. Avoid subtracting their resin twice if the original job has already consumed it. Likewise, record grinding output through the agreed transformation; an unexplained stock adjustment breaks the source link.
For the wider production and inventory scope, explore Apagen’s ERP for injection molding manufacturers. Confirm how recovery records connect with material planning and finished goods traceability.
Measure recovery by material actually used
Ground stock waiting in a warehouse has not yet displaced virgin resin in production. Review approved regrind consumed in authorized jobs, alongside held stock and material with no permitted destination. This gives management a clearer picture of recovery performance.
Consider a simplified example: a job uses 50 kg of approved regrind that replaces 50 kg of virgin resin at an illustrative ₹180 per kg. Gross avoided virgin material cost is ₹9,000. If the attributable recovery and handling costs are ₹2,500, the remaining benefit is ₹6,500 before other applicable costs.
This is a management illustration, not an inventory valuation rule. Use a consistent comparison and avoid double counting costs or savings. Do not claim the full purchase benefit for regrind still held, rejected, or stored without a planned use.
Review collection-to-release time, approved stock age, actual blend compliance, recovery discrepancies, and destinations for released batches. Keep the original defect report visible too. Otherwise, strong recovery numbers can distract from preventable rejects.
Regrind management injection molding teams can verify
Pilot one material family and an approved destination product. Follow full and partial containers, a mixed-source batch, and a quality hold through shift handover and job completion.
Before accepting the workflow, ask the team to demonstrate these cases:
- A missing source label sends material to hold rather than usable stock.
- Grinding input, output, fines, and retained material reconcile in kilograms.
- Held or product-ineligible regrind cannot be reserved for the test job.
- Actual blend quantities use the approved percentage basis and recipe revision.
- A source batch can be traced forward to affected production orders and finished lots.
Also test leftovers. Returned blended material needs its own identity and source recipe; it must not reappear as virgin resin. That small transaction can determine whether the next job’s material record remains trustworthy.
Frequently asked questions
Is 20 or 25 percent regrind safe for every injection molded part
No single percentage applies to every part. Set the limit using the grade, customer requirements, application, and validated process. Record the percentage basis. Approval for one component does not automatically approve the blend for another.
Can we combine scrap from different grades if the polymer and color match
Only through a documented, technically approved combination. Matching polymer names and color does not establish matching fillers, additives, or approvals. Keep grades separate by default. For an approved combination, retain every source and quantity in the new batch.
How do we track regrind generations when every run uses a blend
Link the feed lots and their known histories to the resulting scrap and recovery batch. Define how generations and mixed histories are evaluated. Hold batches with unknown history from applications that require proof; avoid assigning an unsupported number.
Does a supplier certificate for virgin resin also certify our regrind
A virgin resin certificate covers the supplied material, not its later condition after molding, handling, and grinding. Keep it as a source reference. Apply the tests and approvals required for the recovered batch and intended product.
Why does our warehouse show 100 kg of regrind when production can use only 70 kg
The warehouse figure may include held material, rejected batches, or material approved for other products. Check quantity, release status, and use eligibility separately. Plan with the quantity approved for the actual job and report other stock separately.
Can a grinder beside the press feed regrind directly back into production
Yes, within an approved process that controls identity, contamination, blend content, and processing history. Record quantities and material transitions. If the required traceability or blend control cannot be demonstrated, use separately identified recovery batches.
Should we stop buying virgin resin when regrind stock builds up
Base purchasing on dated demand and job-eligible supply. Check batch approvals, upcoming product restrictions, and permitted recipe quantities. A large regrind balance may reflect slow release or limited destinations. It does not automatically replace the virgin resin those jobs require.
Book a demo for your scrap and regrind workflow
Want to connect scrap collection with approved material reuse? Book an Odoo manufacturing demo with Apagen. Bring one material grade, its approved blend rule, and a recent recovery record so we can discuss the workflow your factory needs.
Ask us to show how the proposed ERP handles source batches, grinding quantities, product-specific release, actual blends, and unused material returns. Email sales@apagen.com or call +91 9971800665 to request your demo.