SME CPMod3 CPUpClose 3Apr06

Improving BSO Services and SME Performance Through Cleaner Production: 

Improving BSO Services and SME Performance Through Cleaner Production [DATE] [SPEAKERS NAMES]

Module 3: A closer look at the Cleaner Production process: 

Module 3: A closer look at the Cleaner Production process

Virtual Cleaner Production tour : 

Virtual Cleaner Production tour In this module, we take a detailed “virtual tour” of a CP case example Purpose Provide overview of the CP process Introduce CP tools and techniques

“Midland Metals”: 

“Midland Metals” Enterprise Profile: Based on case study created by the United National Environment Program, Division of Technology, Industry and Economics CASE STUDY country sector ownership established employees revenue Zimbabwe Foundry Family-owned 1998 16 US $65,000

Background: What is a Foundry?: 

Background: What is a Foundry? Casting is one of the oldest industrial processes There are different casting processes. The focus here is: “GREEN SAND” CASTING Midland Metals CASE STUDY A foundry is: a factory that pours molten metal into molds, producing cast metal objects. Some typical cast metal objects: “low tech” “high tech” Turbine blades in jet engines Engine blocks, axles Aluminum pots

Background: SAND-CASTING: 

Background: SAND-CASTING Sand, mixed with clay binder & water (so it will hold its shape) plus coal dust to improve surface finish Pattern (a copy of the shape you want to produce, made of wood, plastic or metal) Basic materials & equipment for green sand-casting Container of molten metal (filled from furnace) Top and bottom mold forms (made of metal, open at top and bottom) Rammer (tool to compact the sand; often a pressing machine is used) Midland Metals CASE STUDY

Background: SAND-CASTING: 

Background: SAND-CASTING MOLDING: Sand placed into bottom mold form & compacted MOLDING: Pattern placed into mold A very basic summary of the sand casting process. . . First of all, mix the sand. 2 1 Midland Metals CASE STUDY THEN

Background: SAND-CASTING: 

Background: SAND-CASTING MOLDING: Add the top mold form 3 4 MOLDING: Fill top form with compacted sand. A tube or pipe provides a path to pour the metal in Pattern is still inside! Midland Metals CASE STUDY

Background: SAND-CASTING: 

Background: SAND-CASTING MOLDING: Take the top mold off and remove pattern & pipe or post 5 6 MOLDING: Replace the top mold and fasten securely! Pouring hole In the middle of the sand is a cavity shaped like the pattern! Midland Metals CASE STUDY

 Background: SAND-CASTING: 

 Background: SAND-CASTING 7 CASTING: Pour the metal (container is filled from furnace immediately before you are ready to pour) 8 Wait for the metal to cool (minutes to days, depending on the size of the casting) Midland Metals CASE STUDY

Background: SAND-CASTING: 

Background: SAND-CASTING 8 SHAKE OUT: Break apart the two halves of the mold & take out the part—usually requires vibrating or striking the mold to break apart the sand CLEANING. Sand is cleaned off the part, the “tab” where metal flowed in must be removed. 9 A copy of the pattern has now been made in metal 10 Mold forms are reused 11 Sand is broken up, screened to remove debris and clumps, and sent for remixing Midland Metals CASE STUDY

Background: SAND-CASTING: 

Background: SAND-CASTING Sand-casting is simple in concept, but demanding in execution. It is a process essential to making basic and advanced products. . . it is also hazardous and energy-intensive! Midland Metals CASE STUDY

Midland MetalsEnterprise Profile, cont’d:: 

Midland Metals CASE STUDY Midland Metals Enterprise Profile, cont’d: products Production volume Markets Iron mill balls & crushing hammers (used for crushing ore) 25 tons/month (planning 10-fold expansion) Mining sector (mill balls) 3-15cm

Foundry process map: 

Foundry process map Sand (new/old), bentonite*, coal dust, water, energy liquid metal Molding Section Dust, gases, mold forms, used sand Dust, gases, noise, reject mixed sand, surplus sand Dust, gases, surplus sand, noise, rejected molds Energy Gases, organic fumes Patterns, mold forms, sand filling, coatings, energy *Bentonite is a mineral clay. It forms a binding agent when mixed with water. Midland Metals CASE STUDY Sand mixing area Molding section Casting area Shake-out & Cleaning area INPUTS Non-Product OUTPUTS Finished products

Initial CP assessment findings: 

Initial CP assessment findings Sand contains significant amount of dust Wind blows sand and dust from stock piles Workers estimate quantities for sand binder and hardener Energy consumption of furnaces higher than normal for similar operations Furnace tap-hole not well sealed after use Liquid metal spills during filling of molds Large number of rejects Sand is lost in each cycle Sand mixing and reclamation very labor intensive Midland Metals CASE STUDY

Material balance for sand mixing: 

Material balance for sand mixing Energy - Electricity = 6 MWh SAND MIXING PROCESS (mostly manual) Emissions to the atmosphere - Dust = 30 t Raw materials - New sand = 135 t - Old sand = 540 t - Coal dust = 55 t - Bentonite = 55 t - Water = 40,320 litres Waste - Used sand = 105 t Products - Moulds and cores = 672 tonnes INPUTS OUTPUTS Annual figures Midland Metals CASE STUDY ! only 75% reclamation efficiency (25% of sand in each batch is lost.)

Sand Mixing: Raw materials costs: 

Sand Mixing: Raw materials costs Midland Metals CASE STUDY (*56 batches/day x 240 days/yr) New sand = 17% of raw material costs !

Biggest CP opportunities: 

Biggest CP opportunities Waste of raw material (sand) During mixing stage Spillage Dust Inefficient use of labor Manual sand mixing Manual screening for sand reclamation RESULT: 4 man-hours required to mix 1 batch Midland Metals CASE STUDY 25% loss = 2000 kg sand per ton product !

Rapid payback CP opportunities: 

Good housekeeping  Better process control  Equipment modification  Input substitution  Rapid payback CP opportunities Midland Metals CASE STUDY Cover the new sand 278 Implement more thorough inspection, segregation of incoming scrap 116 Annual savings (US$) Use sand with low dust content 232 Optimize furnace-melting conditions 139 Train workers to properly handle and measure sand binder & hardner 185 Improvise proper closing mechanism for furnace taphole 28 Install goods spouts on melting pots 28 Total annual savings: $1005

Capital investment CP opportunity: Mechanical sand reclamation/mixing : 

Capital investment CP opportunity: Mechanical sand reclamation/mixing Hopper Conveyor Belt Mechanical Sand Mixer Shaker table with Screen Molds shaken out (Removes lumps) (Transports sand) (Feeds sand to mixer) Midland Metals CASE STUDY Old system: New system: Mechanical sand reclamation plant Manual sand reclamation & mixing

NEW sand mixing material balance: 

NEW sand mixing material balance Energy - Electricity=24MWh Raw materials - New sand = 65 t - Old sand = 610 t - Coal dust = 55 t - Bentonite = 55 t - Water = 40,320 litres Emissions to the atmosphere - Dust = 15 t Waste - Used sand = 50 t was 30 t was 105 t SAND MIXING process (mechanized) was 135 t Increase from 6 MWh Midland Metals CASE STUDY Products - Moulds and cores = 672 tonnes INPUTS OUTPUTS

Profitability analysis:Mechanical sand reclamation/mixing : 

Profitability analysis: Mechanical sand reclamation/mixing Midland Metals CASE STUDY INVESTMENT COST SAVINGS (annual) *even with increase in electricity costs $17,833 ANALYSIS Vs.

Benefits of Cleaner Production: 

Benefits of Cleaner Production Improved Profitability Raw material saving of 25% Labour costs cut by 30% Reduced plant and equipment maintenance costs Improved product quality 5 to 7 fold increase in production levels (pieces/per day), so total profits increase 5 to 7 fold as well Reduced environmental impact Midland Metals CASE STUDY