Thermal Curing

overview all of carbon’s two part resins require thermal curing (also called baking) in a convection oven to achieve their ultimate mechanical properties parts are initially solidified with uv light during printing the thermal cure activates another chemical process that makes parts much tougher safety the oven, parts and accessories may be hot and can cause burns use caution when operating the oven or handling items that have been in the oven always use heat resistant gloves when removing parts from the oven allow parts to fully cool to room temperature before handling for safety for the accuracy of your parts cooling typically takes about 30 60 minutes lma notes https //pim resources coleparmer com/instruction manual/33959 06 pdf https //pim resources coleparmer com/instruction manual/33959 06 pdf a potential fire risk exists if you operate your oven at temperatures in excess of the carbon recommended bake profiles this concern is specific to ovens used to cure epu parts lauryl methyacrylate (lma), which is released during the baking of epu parts, can condense inside oven insulation and/or ducting the amount of lma released will be dependent on the volume of epu parts in a particular bake and how often you are baking with those parts this condensed lma can ignite if exposed to temperatures above what is needed to cure the parts please refer to the sds for lma https //www sigmaaldrich com/msds/msds/displaymsdspage do?country=us\&language=en\&productnumber=291811\&brand=aldrich\&pagetogotourl=https%3a%2f%2fwww sigmaaldrich com%2fcatalog%2fproduct%2faldrich%2f291811%3flang%3den for more specific information about this chemical given our findings, we are updating our user documentation to include these additional recommendations for customers who print with epu resins do not perform bakes at higher temperatures than the bake profile specified by carbon inspect oven and exhaust ducts for presence of condensate if you find condensate, clean it, or replace ductwork refer to the sds for lma prior to cleaning to ensure proper precautions are in place if condensate is noticed after cleaning or replacement, a heat exchanger may need to be installed to cool the ventilation duct to remove the condensate additional recommendations bake ce/epx and epu parts in separate ovens ce and epx require a higher temperature to bake clearly label ovens with maximum allowable temperatures for bakes as specified for products by carbon do not exceed the carbon recommended bake temperatures yamato ovens are equipped with independent overheat protection refer to the thermal curing docid 7ne6rgdaszpapohh5qozm in the instruction manual to understand how to set overheating protection for your specific oven consult your facilities and ehs staff on proper handling of lma condensate in the exhaust system and proper personal protective equipment for handling of lma contaminated exhaust components and associated duct work baking equipment go to accessories & supplies docid 95twe3ttl 5ihi6dnl4xi for purchase links to many of the products listed below yamato convection oven this programmable, convection oven is the central component of thermal curing it is able to store up to 6 different programs at once larger facilities should consider purchasing multiple ovens to minimize downtime see oven programming docid\ fze0 qdahovhnvvm6l6kk for instructions on creating baking programs for the resins that you use instruction manual english https //archbee doc uploads s3 amazonaws com/uxbzokjjtgpphjapq8fvm tpgdploiz7z9slxsurqfx 20250131 225002 pdf ce certificate english https //archbee doc uploads s3 amazonaws com/uxbzokjjtgpphjapq8fvm z2vlnitdtlhqjzbyzy0ij 20250131 225512 pdf ceramic baking sheets ceramic baking sheets work well for curing most carbon resins due to their durability and non stick properties placing parts directly on the tray works well for the following resin families rpu, fpu placing parts directly on the tray is not recommended for epx or sil resins writing notes on the tray writing notes on the tray with a felt tip pen can help identify parts after baking notes are easily removed with ipa after baking exercise caution with previously used trays with baked on resin parts tend to stick to resin residue on dirty trays thoroughly cleaned parts will not leave behind baked resin on your tray parts may have a non uniform texture non uniform texture where they directly contact the tray nonstick aluminum foil nonstick aluminum foil works well for parts that are more prone to sticking to the baking tray for optimal surface finish, ensure that the foil is completely flattened all resins are compatible with nonstick foil most useful for epu, sil and epx nonstick foil also works well to keep trays clean do not use standard aluminum foil, which will stick to parts silicone sheets silicone sheets can be used to line baking trays silicone helps preserve your trays when silicone degrades or becomes coated in residual resin, discard and replace any residual resin left on silicone from previous bakes can stick to parts parts may have a non uniform texture where they directly contact the silicone pan mesh the pan mesh is a flexible, heat resistant grid best used for parts with thin walls or flat parts that are prone to warping allows all surfaces to be equally exposed to air for uniform evaporation of solvent and uncured monomers when baking parts on a mesh, use the following 3 items in order ceramic baking tray on the bottom drying rack on the tray pan mesh on the rack this is the ideal setup to promote airflow around parts the pan mesh may leave marks on parts baking tray, rack and mesh example of parts on pan mesh basic workflow prepare the parts ensure that part(s) are thoroughly washed and dried per standard washing protocol prepare baking implements clean the non stick baking tray with ipa to remove any residue make sure all surfaces are dry before placing parts or putting the tray in the oven options line the tray with non stick aluminum foil lining your tray with non stick aluminum foil will preserve your baking sheet and keep parts clean some resins/ parts may stick to the bare ceramic tray especially if the tray has baked on resin from a previous bake (which cannot be cleaned off) put tray with parts in oven place the parts on the clean tray carefully put the tray in the oven close the oven door start the oven on the oven controls, press the program button program button to select the appropriate program for the resin programs will show in the set temp window prg1, prg2, and prg3 prg1, prg2, and prg3 consult the lab reference grids docid\ ujf4k0ny4lye74zohx1r or the resin protocol sheet for the appropriate baking schedule press the enter button enter button to confirm the program and enter pattern mode pat pat will be displayed in the °c window press up or down arrows up or down arrows to select the appropriate pattern pattern numbers will display in the set temp window press and hold run/stop button run/stop button until you hear a click, indicating that the curing cycle has begun the heater led light will also begin blinking example video the following video demonstrates choosing program 3, pattern 1 which in this example is programmed for rpu 70 this video does not have audio remove parts from the oven wearing heat resistant gloves, remove the pan from the oven and allow it to cool ( 27° c) alternately, parts may be allowed to cool inside the oven as well when the production workflow allows workflow video video text place uncured part on metal tray with grid grid promotes even curing and helps prevent warping carefully place tray in oven and close door use caution oven may be hot use caution oven may be hot press program button to select correct program note the video mistakenly says "pattern button " press enter button to confirm and enter pattern mode press up or down arrows to select pattern press run/stop button 2 times to begin curing cycle when cycle is complete, put on heat resistant glvoe and remove part from oven use caution oven, parts and tray may be hot use caution oven, parts and tray may be hot set part aside to cool before handling your part is now cured salt baking see salt baking docid\ whftudzdy0cs0a0 dljcm for instructions for curing your parts while nested in salt hanging the majority of parts are baked on a tray however, some parts are best baked by hanging them ideal for thin, light, oddly shaped parts with a feature (hole or hook) suitable for hanging allows for uniform heat distribution, which decreases the chance of deformation and surface imperfections the material coupons shown in the image are designed to be threaded onto a keychain the hole for mounting the coupons works perfectly as a feature to hang the parts from during baking tips load parts onto a wire or rod hold parts by edges hold parts by edges or other non cosmetic surfaces to prevent scratches or other surface defects to cosmetically important surfaces ensure that parts do not touch each other parts do not touch each other or they will fuse and bake together they will fuse and bake together allow parts to cool to room temperature in hanging position cooling can occur in oven or outside of oven if cooling outside of oven, be sure to support parts so they may hang while they cool exercise caution when loosening parts from wire to avoid chipping chipping most resins will slide off easily, but ce may stick to the wire hanging with wire loops requirements perforated rack steel wire or paper clips lengths of stiff wire or thin rods oven safe weights instructions bend 2 wires into upside down u shapes with a loop on each end 2 wires into upside down u shapes with a loop on each end these loops will hold the rod loaded with parts lower bent clips through holes of rack bent clips through holes of rack so the u shapes hang down space the clips so they hold rod place weight on top of each wire weight on top of each wire u to hold it steady while loading the rod of parts carefully hang rod of parts from wires remove weights after loading or keep them in place throughout the bake hanging with binder clips requirements grill racks binder clips thin rods or stiff wires instructions clip 2 binder clips 2 binder clips to the oven rack from below space clips so that they can safely hold a rod of parts hang rod of parts hang rod of parts from binder clip loops hanging below rack baking fixtures baking fixtures are used to support parts during the thermal curing process they are especially useful for parts with delicate features, long protrusions or any features that require a high degree of accuracy disposable baking fixtures salt baking nonstick foil shaping foil to support overhangs can be used as a quick, low cost and disposable baking fixture reusable baking fixtures production runs are well suited to fixtures for repeated baking cycles designing fixtures to specifically support a part during the bake can maintain part accuracy and prevent deformations loctite ind147 docid\ e2xwjdkbpkrmfpaccheu0 fixtures this temperature resistant one part resin is well suited to creating custom baking fixtures machined aluminum if parts are sticking to the fixture ensure that the part is fully clean apply a noise texture to the fixture and/or part to minimize direct contact use non stick foil between the part and the fixture as a mold release use a teflon mold release spray other materials compatible with baking temperatures it is not recommended to weigh down parts during baking weighing down parts can contribute to warpage due to uneven heat distribution and mass loss