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Optimal RH%

Discussion in 'General Questions' started by Lance Weston, Oct 24, 2021.

  1. Lance Weston

    Lance Weston Active Member

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    I have modified a couple of Sunlu Dryer boxes to regulate both temp and RH. If both the RH is too high and the temp is too low then the heater turns on.

    I loaded a new roll and started printing at an RH of 40%. I set the box to bring the RH% down to 15%. As I started printing I could see some improvement in finish quality over the first two days. Now the Indicator strip in the box indicates that I got down to 10% RH and my print quality seems not to be as good.

    What is the optimal RH% for printing PLA?
     
  2. Jerome Helbert

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    I have two large 82 quart airtight containers that I store all of my filament in, as well as several two dryboxs that I can print directly from that are based off of cereal containers. I have a large amount of desiccant in them all (probably way more than is necessary, but I have to refresh it considerably less often.

    According to the sensors I keep in each of them, I run 1-2% RH in all of them (the sensor has +/- 5% accuracy below 10% RH, but it's so low it's probably in the ballpark. I have zero issues with print quality. I have them mostly for print polycarbonate and nylon, but use them for all my filaments now and have never noticed an issue.
    Capture.PNG

    I've always assumed lower is better.
     
    wsam and mark tomlinson like this.
  3. Lance Weston

    Lance Weston Active Member

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    There are so many variables and I tend to think the thing changed is responsible. I have to get this installed on a few printers to see if I am fooling myself. My current method was to take a spool, load it in and save parts every 12 hours as the RH% went down. I then compared finish on the parts which is pretty subjective. I found that 20%RH was the best finish for PLA. I will repeat this over many rolls and see if it repeatable. Thanks for your info..
     

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