7 Lower Specific-Gravity with BMC Part Weight ReductionLower Specific-Gravity with BMCBMC Polyester : 1.7 – 2.05s.g.Die-Cast Aluminum : 2.6s.g.Die-Cast Zinc : 6.9s.g.Reduction In Assembly / Unit WeightLower Raw Material Content $Reduction in Shipping Weight / Cost $
8 No Secondary Machining BMC Parts molded GATE FREE. No Secondary Gate RemovalNo material overflows required for BMC. No secondary trim-die operation requiredCritical dimensions / tolerances typically held as-molded. No secondary machining operations required.Package At Press!
9 Tooling FriendlyBMC Polyesters are very “tooling-friendly” offering the following advantages over metals:4-5 Times Longer Mold LifeHigher CavitationsSignificantly lower PM & Repair CostsAllows for use of more complex moving actions (Slides etc.)Allows for use of manifold systems for material delivery to cavities
10 Greater Design Freedom The flow characteristics and related moldability of BMCs allows for the formation of more complex part geometries.This gives the part designer increased freedom to:Incorporate the net-shapes required to optimize the part / assembly designReduce the number of components through consolidation of parts
11 Motor Bracket Configurations Commutator End Brackets / End BellsFan End BracketsClamshell MotorsMotor End Plates“Cup” Style Motor HousingsFan / Diffuser End CapsBrush PlatesBrush Cartridge Housings
12 Commutator End Bracket / End Bell Integrated Brush Box FeaturesAs-Molded Bearing Bore, Brush Boxes & Field Pads
13 Fan End Brackets Integrated Airflow Features As-Molded Bearing Bore & Field PadsMounting Points Suitable for Motor Assembly
14 Clamshell Motor Housings As-Molded Bearing BoreAdvantages in Small Hand- Held ApplicationsWeight ReductionNoise / Vibration ReductionGround-Path Insulation
15 Motor End Plates As-Molded Bearing Bore Weight Reduction on Large Motor Configurations
16 “Cup” Style Motor Housings Reduced Number of Components in AssemblyMore Consistent Motor AlignmentAs-Molded Bearing Bore, Brush Boxes & Field PadsIntegrated Airflow Features
17 Fan / Diffuser End Caps* Accommodates the formation of more complex / efficient airflow geometries
18 Brush Plates / Cartridge Housings Superior Properties over Thermoplastics
19 BMC Motor Bracket Materials BMC Materials currently supplied into motor bracket applications:BMC 400BMC 620BMC 1412T40-(18)T40-(20)T40-(25)BMCI can custom-formulate materials as-necessary to meet specific applications.
20 Case Study #1 Commutator End Bracket Conversion AluminumBMCMaterial Cost / Part:Molding Cost / Part:Secondary Gate Trimming:Secondary Machining:3%Total Cost / Part:$.19$.281$.01$.035$.015$.531$.14$.225-$.011$.37630% SAVINGS
21 Case Study #2 Commutator End Bell Conversion/Redesign Brush Boxes incorporated into BMC part as 1-Piece DesignAluminumBMCMaterial Cost / Part:Molding Cost / Part:Secondary Gate Trimming:Secondary Machining:3%Brush Plate (2nd Part):Total Cost / Part:$.08$.22$.01$.035$.001$.217$.563$.133$.23-$.011$.37434% SAVINGS
22 Mounting Hardware for BMCs Self-Tapping ScrewsThread-Cutting Never Thread-Forming“BT”-Style or “Type-23” Style recommendedHigh-Low thread preferredHole diameter +.002” p/s over root-diameter of screwMinimum thread engagement 2 ½ X screw diameterHole depth 125% to 150% of screw engagement depthMounting boss diameter minimum 2X major screw diameter
23 Design Considerations for BMC Minimum Recommended Wall Stock .070”Recommended Nominal Wall Stock .100” ”Minimum draft 1-degree P/S (Excluding Bores & Brush Boxes)Consistency of Wall stockCore-out Thick Sections Wherever PossibleFillet Radii Wherever Possible“Line-of-Draw Features Wherever Possible
24 BMC offers cost savings without sacrifice. The BMC AdvantageFaster CyclingLonger Tooling LifeNo Costly Secondary MachiningWeight ReductionNoise ReductionDimensional StabilityDesign VersatilityBMC offers cost savings without sacrifice.