AFS Sand Casting Conference Coatings Panel. Presented by AFS 4F

Transcription

1 2014 Coatings Panel Presented by AFS 4F Mitchell Patterson - HA International Tim Maurina C A Lawton Jeff Cieplewski Prince Minerals

2 Coatings Overview Mitchell Patterson HA International

3 What is a Refractory A coating is a protective material, applied to a core or mold, to enhance the surface finish of the casting and reduce casting defects which occur at the sand - metal interface. Coating?

4 What Can a Coating Do? Fill Voids, Provide a Finer Barrier Increase Refractoriness Direct Gas Improve Sand Peel Control Chemistry at the Mold Interface

5 Coating Composition Refractory Guts of the Coating Application Properties Carrier Suspension Agents Binder Additives

6 Refractory Name Chemical Name Melting Specific Hardness Particle Shape Point (F) Gravity (MOH) LOI % Graphite Carbon Flake/Amorphous Zirconia Zirconium Oxide Round Zircon Zirconium Silicate Eliptical Chromite Iron Chromium Oxide Round Alumina Aluminum Oxide Round Mullite Aluminum Silicate Needles Kyanite Aluminum Silicate Needles Silica Silicon Oxide Round/Angular Kaolin Hydrous Aluminum Silicate Platelette Olivine Magnesium Iron Silicate Angular Talc Hydrous Magnesium Silicate Platelette Pyrophylite Hydrous Aluminum Silicate Platelette

7 Coating Carrier Water Alcohol

8 End Markets Jobbing High Production

9 Jobbing Large Molds Water and Alcohol Flow Coat, Spray, Brush Application Main Requirement is Protection High Temperature Refractories

10 High Production Smaller Castings Water Dip Application Many Potential Requirements Finish, Peel, Anti-veining, Gas, etc Low Melting Refractories Attention to Application and Throughput

11 Trends / Technology Low cost alternatives to high temperature refractories Improved rheology High mileage coatings

12 Best Coating Practices For Large Castings Tim Maurina C.A. Lawton

13 Best Coating Practices For History Large Castings CA Lawton is a 5 th Generation Company Been in Business for 135 years Casting size from 400# to 15000# Pattern shop, Foundry and Machine Shop Serve Mining, HVAC, Oil & Gas and Water Industries

14 Best Coating Practices For Large Castings Flow coat 95% of molds and cores Mixing Process Control Application Housekeeping

15 Best Coating Practices For Mixing Tank is heated in the winter to maintain temperature Tank is filled from totes Level of coating in tank is checked at beginning of each shift Large Castings Coating is mixed 15 minutes at beginning of each shift and periodically during the day

16 Best Coating Practices For Process Control Coating is tested every 2 hrs. per shift Check temperature Weight per Gallon( Mud balance scale) Viscosity (Din cup) Mil Thickness Coating is adjusted as needed to keep in range Large Castings

17 Best Coating Practices For Application Molds and cores are coated in 2-3 coats Coating is allowed loose gloss between coats Most mold and cores require mils Large Castings

18 Best Coating Practices For Housekeeping Before being placed on flow coat station molds are prepped After being set on coating station molds are blown out again The pan is blown out before coating molds Large Castings

19 Best Coating Practices For Housekeeping After coating of molds excess coating is removed from the pan Sand trap on coating station is cleaned two times per week Large Castings

20 Best Practices for High Volume Castings Jeff Cieplewski Prince Minerals

21 High Production Dip Application (water-base, ceramic-graphite) Small to medium-sized cores (high-volume) Dipped by hand, robotics or manipulator Application yields the greatest amount of sand penetration and surface deposit Short rheology no runs / no drips Longest to dry Little mess Simple design to dip tanks

22 High Production Proper Mixing Techniques Quality Control Expectations

23 High Production Proper Mixing Technique Re-mix coating before using; make homogeneous Propeller blade on mixing shaft; single blade Enough horse power / air pressure to turn shaft & blade Roll the coating; do not vortex

24 High Production Proper Mixing Technique

25 High Production Proper Mixing Technique

26 High Production Proper Mixing Technique Homogeneous Non-Homogeneous

27 High Production Proper Mixing Technique re Single Shaft w/ Propeller Blade Low-Shear Propeller Blade

28 High Production Quality Control Baume measure specific gravity» Baume Gauge» Down and dirty test» Gets you close enough» Establishes a working range» Highly operator dependent (source of error)» Function of density and viscosity

29 High Production Quality Control Viscosity flow-ability» Zahn Cup, paint cup or paint funnel» Somewhat lengthy compared to Baume» Establish a working range» Operator dependent» Beware of air entrapment in coating

30 High Production Quality Control Density weight per unit volume» Gardner Cup or Mud Balance» Somewhat lengthy compared to Baume» Measures ratio of coating to water» Establishes a tight working range» Less operator dependent» Highly reproducible results» Beware of air entrapment in coating

31 Expectations High Production Performance not a cure-all; dependent on core and mold quality; dependent on ability to control all foundry variables Settling keep material mixed; dead spots in tanks; over-dilutions Spoilage dirty water ; rotate stock; clean equipment Drying water needs to evaporate; air movement and heat Rheology Runs and drips, puddles, other surface flaws; use of blow-offs Stability Check coating properties as needed ; adjust coatings when out of at-use levels

32 Summary High Production Coating formulations Application, resin system, sand type, drying methods No bad way to apply coatings if correctly matched and controlled Coating control tools are effective when used properly

33 For additional information, please contact: Mitch Patterson HA International Tim Maurina C A Lawton tmaurina@ calawton.com Web Site Address Jeff Cieplewski Prince Minerals jcieplewski@princecorp.com