Buehler Cast N Vac 1000 Embedding System

Transcription

1 Buehler Cast N Vac 1000 Embedding System Standard Operating Procedure Revision: 1.0 Last Updated: Nov , Revised by Matt Bilton Overview This document will provide a detailed operation procedure of the Buehler Cast N Vac 1000 Embedding System. Formal Training is required for all users prior to using the system. Revision History # Revised by: Date Modification Document No. 1

2 Table of Contents Overview... 1 Revision History... 1 Table of Contents... 2 General Information... 3 Main components:... 4 Safety... 5 Operation... 6 Consumables and Accessories... 7 Making a mount... 7 Recommended Curing Times... 8 After use... 9 References and Files... 9 Contact Information

3 General Information Buehler s Cast N Vac 1000 evacuates trapped air from specimens. Without the presence of air, the mounting compound fills the specimen pores and eliminates gaps between the specimen and the compound. As a result, edge retention is enhanced and fragile samples are supported during grinding and polishing. The vacuum pump supplies sufficient vacuum to quickly evacuate trapped air from any porous specimen. The high strength plastic chamber maintains vacuum throughout casting by means of an O-ring seal. Several samples may be prepared at one time using the rotary table within the vacuum chamber. 3

4 Main components: Gauge Vacuum pump Cup holder Vacuum hosing O-ring seal Filtering flask Vacuum chamber Molds Stage rotation Paper cup button for resin Figure 1: Main components of the Cast N Vac embedding system 4

5 Safety The Cast N Vac 1000 is designed for use in dry, indoor laboratory environments, away from strong electromagnetic fields and within normal temperature ranges (5 40 C), and non-condensing humidity ranges (30 90%). Important safety instructions: Only trained users are permitted to operate the Cast N Vac system. Always use the system within a fume hood (Wetbench 9). Wear safety glasses, protective gloves and a lab coat at all times. For hot specimens, always handle with heat protective equipment (e.g. gloves). Do not operate the machine in the presence of flammable liquids, gases or dust. If there is a problem with the tool, do not attempt to repair yourself. Always speak with a tool owner. Resin handling and care: Uncured liquid epoxy resins and hardeners can be irritant to the eyes and skin, as well as toxic to aquatic organisms. To prevent risk of exposure, all handling of the resins, hardeners and use of the casting system must all take place within a designated fume hood (Wetbench 9). o Cured (solid) epoxy resins are generally classified as non-hazardous, and so only when cured can molds be removed from the fume hood. Solid resin waste can be disposed of safely in the general bin. Stirring sticks for the resin must also be left to cure before solid disposal. Liquid resins and hardeners must never be disposed of in a drain. When possible, allow the waste resin to cure fully before disposing as solid waste. o In the event of a spill, scoop or wipe up resin with an absorbent paper towel. Clean the area and any tools with detergent solution. Place any solid waste within a plastic zip-lock 5

6 bag and wait for any resin to dry before disposing in a solid waste bin. Refer where necessary to the appropriate MSDS sheet for the epoxy resins and hardeners. o Always notify a 4D LABS member of staff, who can assist with a safe clean-up. Operation 1. Set-up the equipment inside the fume hood (Wetbench 9; see Figure 2). 2. Take care when moving each component into the fume hood. The Turbo Pump is heavy, and may stick to the floor with its rubber suction feet. Ask a member of staff for assistance if necessary. 3. Connect the vacuum hose line between the Turbo Pump and the Filtering Flask. Take care when handling the glass rod connector to the Filtering Flask, as this is delicate and can easily break. 4. Connect the second vacuum hose line between the Filtering Flask and the Vacuum Chamber. 5. Plug in both the Turbo Pump and the Vacuum Chamber into the mains power supply. Figure 2: Embedding system set-up within the fume-hood 6. Before use, check that the vacuum hose assembly is secure. 7. Check the O-ring seal in the Vacuum Chamber is lined with vacuum grease. Apply a light film of vacuum grease if necessary (grease is stored in , ask a member of staff for any assistance). a. Do not apply an excessive amount of grease, as this can cause the lid to move under vacuum. 6

7 8. Place a protective paper liner on the bottom of the chamber (do check as the previous user may already have placed a clean liner). Place and position the molds containing specimens on the liner. a. Use an empty cup on the cup holder to determine the resin flow position in relation to the centre of the mold. 9. Seal the chamber by ensuring the vacuum gauge is turned such that the relief opening is not aligned with the atmosphere hole. Consumables and Accessories Items required for use with the Cast N Vac are currently stored in room (Nanoimaging). These include: Mold cups Resins Stirring sticks Polystyrene cups Paper chamber liners Vacuum grease Ask a member of staff if you require any assistance. Making a mount 1. Select the appropriate resin for your sample. Refer to the supplementary Technical Information Guide on Castable Mounting Compounds. 2. Mix the resin in a polystyrene cup. To avoid being wasteful please use only the volume that you need. Use 10g approx. of resin + hardener per mount. a. For Epoxy Cure use 100 parts resin to 23 parts hardener (by weight). For an approx. total 10g: use 8g resin to 1.85g of hardener. Measurement do not have to be precise, just close. b. For Epoxy Thin use 100 parts resin to 45 parts hardener (by weight). For an approx. total 10g: use 7g resin to 3.15g of hardener. 7

8 c. For Epoxy Heat use 100 parts resin to 20.6 parts hardener (by weight). For an approx. total 10g: use 8g resin to 1.64g of hardener. 3. Carefully pinch one side of the cup s edge to form a spout for a more controlled pour. 4. Place the cup into the cup holder. 5. Adjust and tighten the cup stop to prevent the cup from slipping or falling out when the cup is tilted. 6. Place the plastic dome on the vacuum chamber, ensuring good contact with the vacuum seal. 7. Start the vacuum pump. 8. When the gauge reads 559 Torr, turn off the pump. 9. Slowly rotate the casting-knob counter-clockwise to pour the resin into the mold(s). a. NOTE: After pouring, do not immediately raise the cup to a vertical position. Keep the cup slightly tilted until the resin stops dripping. 10. Only fill the molds half full to prevent the resin from spilling during the vacuum stage. The remaining space can be filled after the chamber is open to atmospheric pressure. 11. Press the revolving table switch to move the next mold into position. 12. Once all molds have been filled, slowly rotate the base of the vacuum gauge so the relief opening is aligned with the atmosphere hole. This allows air to slowly enter the vacuum chamber. a. Do not completely remove the vacuum gauge from the plastic dome. The sudden rush of air into the vacuum chamber may disturb the resin causing the resin in the molds to spill or splatter. 13. Once the vacuum in the vacuum chamber has dissipated, the vacuum chamber can be opened and additional molds added for encapsulation. a. Allow the mounts to completed cure before performing any further preparation steps. Recommended Curing Times 1. For Epoxy Cure: cure time = 6 hours (Temp < 40 C) 2. For Epoxy Thin: cure time = 9 hours (Temp < 30 C) 3. For Epoxy Heat: cure time = 90 minutes at 55 C. Use vacuum oven in the Thermal Processing Lab. 8

9 More details on the use of each epoxy type can be found on the supplementary Technical Information Guides. After use 1. Remove your embedded samples carefully from the molds 2. Please clean the molds of residual resin using isopropanol and Kimtech wipes (always wear gloves). Place wet wipes into the organic waste bin. 3. If contaminated, dispose of the protective liner from the bottom of the vacuum chamber and replace with a clean liner. Dispose old liner into the Chemical Solid Waste bin. 4. Dispose of your polystyrene cup (waste resin must be cured) into the Chemical Solid Waste bin. References and Files Buehler Cast N Vac 1000 Operators Manual Technical Information Guide: Castable Mounting Compounds (Buehler) Technical Information Guide: Final Polishing & Preparation Guides (Buehler) Contact Information Questions or comments in regard to this document or Buehler Cast N Vac Embedding system should be directed towards Xin Zhang or Matt Bilton (zhang@4dlabs.ca; bilton@4dlabs.ca; ) in 4D LABS at Simon Fraser University, Burnaby, BC, Canada. 9