Resin Bottle Funnel Adapter

prusaprinters

This design allows attaching a 2-liter bottle to a resin bottle. The 2-liter bottle can be cut and used as a funnel to drain the SLA printer resin vat back into the resin bottle. The 2-liter bottle makes a great funnel and is large enough to have a filter placed inside. The adapter is threaded for both the 2-liter bottle as well as the resin bottle.I had seen funnels that were made from 2-liter bottles, but I found them to be prone to falling over since it would just sit on the bottle. I decided to make and adapter that would thread onto the resin bottle as well as the 2-liter bottle. This way the funnel could not fall off.I designed this with a little extra clearance so that it threads onto both bottles easily. It does not need to seal, just mount on the bottles and not fall off.I have printed this with both FDM and SLA printers. For the FDM print, I printed it upside down (tapered section at the bottom) and use an outer brim. No supports were needed.For the SLA print, I also printed it upside down and tilted at a 45-degree angle. Danger, technical details for makers!  Who knew bottle thread forms were so involved! Since it took a lot of research and experimentation to get the thread forms correct, I thought I would share my findings. The 2-liter bottle uses a PCO1881 thread. The following links are for the details of the thread spec. After a lot of analysis, I determined that the resin bottle uses the PCF-38P-4 thread form (or a variation of it).Soft drink bottle top thread sizes (imajeenyus.com)ISBT - ISBT Threadspecs Downloads3784253-21.pdf (isbt.com)  ← PCO1881pcf38p4.pdf (isbt.com)   ← PCF-38P-4