ArticlesWater Heater Pan

Design for Manufacturability Cost Reduction

This water heater pan is a structural, load-bearing molded component that supports the full weight of a water heater. UPM redesigned the part using Design for Manufacturability (DFM) to meet a 600 lb. load requirement at a production-viable cost, reducing the unit price by approximately 66% while preserving full structural performance.

Overview

An OEM in the water-heating equipment industry approached UPM to manufacture a structural base pan designed to support 600 lbs. with a safety factor of 4. The original design, developed by the customer’s engineering partner, called for 30% glass-filled nylon with a part weight exceeding 24 lbs. At that weight, the part required a 2,000-ton press and carried a unit cost of $78.25 per piece at production volume. UPM’s DFM-driven approach brought the part well below that cost while preserving full structural performance.

The Challenge

The customer needed the part to meet strict structural requirements at a commercially viable price point. Initial quoting revealed that material cost and press tonnage were the two primary cost drivers. Reducing part cost without compromising load-bearing performance required rethinking the design from a manufacturing perspective.

UPM’s DFM Approach

UPM’s sales and engineering team collaborated directly with the customer’s product designer to evaluate wall thickness, rib geometry, and material selection:

• Wall thickness reduction: Walls were reduced to 0.150″, cutting part weight from over 24 lbs. to 8.37 lbs.—a 65% reduction.
• Rib optimization: Ribs were extended to the floor of the part, maintaining the 600 lb. load capacity while using significantly less material.
• Material change: Corrected stress simulation data confirmed that polypropylene (PP) could replace the costlier 30% glass-filled nylon, passing all load requirements at a fraction of the resin cost.
• Press downsizing: The lighter, thinner part dropped clamp requirements from a 2,000-ton press to a 1,000-ton press, reducing machine-time costs.

Results

The redesigned pan improved on every key metric:

Key Takeaway

By engaging early in the design process and applying DFM principles—wall thickness optimization, rib geometry refinement, material substitution, and press-size analysis—UPM brought a part that was well over budget down to roughly one-third of its original unit cost. The mold investment remained comparable while unit economics improved by approximately 66%, enabling the customer to move to production within 30–45 days of approval.

^{UPM (Universal Plastic Mold) is an ISO 9001:2015 certified, IATF 16949 compliant custom plastic injection molder based in Baldwin Park, California, operating 30 injection molding presses from 150 to 2,000 tons.}