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Casting Scrap by Defect Pareto Worksheet

Foundries rarely lack scrap data, they lack scrap data in cost terms. This worksheet turns defect counts into dollars so that the Pareto reflects money, not just piece counts.

Download:
DefectWhere foundPieces scrappedCost per pieceScrap costWeek ending
$539
$281
$192
$246
$100
Total pieces scrapped
90
Total scrap cost
$1,358
Average cost per scrapped piece
$15

Sort the exported sheet by scrap cost, highest first. Count alone misleads: a few late machining rejects can cost more than many early shakeout rejects.

Turn scrap codes into a cost view

Optional: a short review of how ERP scrap data could feed a defect cost report.

Optional. The tool and every export work without this. No spam.

How to use this worksheet

Add a row per defect, per place found and per week. Enter pieces scrapped and the cost carried by one piece at that point in the route. Scrap cost calculates automatically and totals update. Export to Excel and sort by cost, then chart the top three or four causes. The vital few typically carry most of the loss.

Why cost, not just count

A casting scrapped at shakeout has only melt and mold cost in it. The same casting scrapped after machining carries labor, tooling and overhead. Two defects with equal counts can differ in cost several times over. Using cost per piece at the point of discovery ranks defects by what they cost you, and it shows the value of finding defects earlier, for example with radiography or pressure checks before machining.

Reading the results

Average cost per scrapped piece rises when late stage defects dominate, even when total scrap count is flat. Use that figure with the share by defect to choose projects. Shrinkage and gas porosity usually point to gating, risering, venting or moisture. Sand inclusions and core shift point to molding and core setting. Track results week by week to verify that an action worked.

Common mistakes

Mixing rework with scrap, using standard cost for every stage, and lumping unlike defects under 'other' all weaken the analysis. Keep defect names consistent between shifts and with your ERP scrap reason codes so data from the floor and from the system match.

Frequently Asked Questions

What cost should I use per piece?

Use the accumulated cost at the stage where the piece was scrapped, such as melt and molding at shakeout, or including machining after the cut. A consistent rule matters more than perfect precision.

Is this a true Pareto chart?

It gives you the data. Export to Excel, sort by cost descending and add a cumulative percent column and chart if you want the classic bar and line view.

Should rework be included?

Track rework separately or in its own rows with a clear label, so scrap totals are not inflated. Rework cost can be significant and deserves its own analysis.

How often should I update it?

Weekly works for most foundries, daily for high volume lines. The point is catching a trend before a full lot is affected.

If your scrap reason codes sit in an ERP, Netray can help pull them into a defect cost view on your own servers.