[3D Printer Series] Hotend cooling

 Hotend Cooling and Testing

The hotend on the Sapphire Plus is supposedly pretty bad but so far I haven't experienced any clogging that wasn't my own fault (didn't push the PTFE tube all the way in) even on an 8 hour print. This is with PLA so perhaps the hotend is sufficient for the low temps (205C). My plan was always to start printing some higher temp filament like PETG/ABS/ASA and perhaps even PC and Nylon so I knew I would need an all metal hotend at some point. I decided on the Triangle Labs Dragon, specifically the high flow version. This seemed like a good compromise between performance and price. 

The Mount

To use it I would need to print a bracket to be able to use it on the Sapphire Plus. I chose The Mint Mount by 3D-One. This mount was fairly recently developed to be compatible with the dragon. After printing out the mount and installing the dragon, I did notice some gaps around the hotend which in my mind seemed like wasted cooling air flow so I embarked on a test to see what configurations would yield the best performance.

Mount seems to have gaps that may waste cooling airflow

The test rig

I purchased the Kaiweet Multimeter because it came with one of those tiny glass bead thermistors and I needed a better meter that could do things like true RMS and could measure PWM signals. For the price this is a really good deal. One simple feature that I love is that it has a built in stand!

Next I transferred the components from the original hotend to this mount. For the cooling fan, I purchased the Anvision 40mmx10mm 24v fan (currently sold out on amazon) because it seemed like they made fairly quiet fans. I connected the fans by crimping on some JST-SM connectors (the connector I use for all my hotend connections).

I then placed the thermistor from my multimeter fairly deep into the hotend. I used my fingers to gauge exactly how far the thermistor should go as you can see in the photo below.

 

Here's what it looks like with the thermistor inserted. Its a fairly snug fit so I doubt it will move during my tests.

Here's my mess and my full testing setup.

Test Parameters

I tested fan pull and push as well as with and without gaps, 4 total combinations. To fill the gaps I just stuffed some small pieces of tissue into the gaps between the cage and the mount. Since I knew the replacing of fans and the insertion/removal of tissue might move the thermistor, I figured the best way to verify it didn't was to just repeat the first test and see if I got the same results.

The room temp was 70F (my meter was in F). For each test run, I set the hotend temp to 205C (Klipper uses C) and I waited till the temp on my meter to stabilize (~ 5min) and then set a timer for 5 more minutes to confirm the temp didn't change. After each test I turned off the heater and setup the hotend for the next and waited for the temps to get down to the low eighties F before starting up the heater again.

Test Results

	Gaps Open	Gaps Filled
Fan Push	99F	95F
Fan Pull	90F	93F

Conclusion

It looks like for my particular setup Fan Pull with the gaps open proved to be the winner. What's interesting is that there's no consistency between whether you should have gaps filled or not. That's why it's important to do your own tests. Your hotend geometry, the fan you use, and the mount are all variables that affect cooling performance. Changing any one of them and you could very well get different results.

Choosing a 3D Printer

Key Factors 

It's important to get a list of factors that are relevant to you when deciding on what printer to by. Here are mine:

• Price < $1000
• Speed, can print accurately at relatively high speeds
• Quality
• Large build plate
• Serviceability
• Support/Community support

For me, based on some reviews on YouTube and Facebook, I decided to go with the TwoTrees Sapphire Plus. It seemed to have the best hardware for a machine with a 300+mm build plate. Because it’s a coreXY printer with linear rails it has the potential to move swiftly and accurately. The biggest downside is that it’s not beginner friendly nor is there any support from TwoTrees except from their Facebook Group, which in most cases is community support not manufacturer.

I also considered the ender 5 plus but learned that it’s not a true corexy printer. I also looked at the SecKitGo but that felt like a bigger project and the developer had stopped taking orders. 

Multiple versions floating around

If you want to order one, I don’t suggest you use my amazon affiliate link, instead you can get the same one I got from 3dprintersonline.com which is much cheaper. If you do so be aware that you might not be getting the true 'latest' version that at the time of this writing supposedly has a glass bed and a synchronization belt between the 2 z-axis motors. The latest one according to other accounts can be got  from gearbest (pay more) and/or ordering from the china warehouse. I didn't feel like waiting or paying more so I went with 3dprintersonline.com.

3dprintersonline.com

This site seems a little sketchy to me but searching the net revealed they are legitimate. For the purposes of their relationship with TwoTrees, they are more like a marketplace that takes orders for them and funnels those orders directly to the TwoTrees warehouses for fulfillment. My order seemed to be delayed getting out the door so it took a couple of emails to 3dprintersonline who then emailed their rep at TwoTrees to check on the shipment. Bear in mind this was after the Black Friday sale so your experience might be better.

Would I choose the Sapphire Plus again?

Knowing what I know now, I probably would but for the first time 3d printer owner who doesn't want to tinker with one I would 100% not recommend it. If you just want something that works, you're better off with a Prusa ($$$) or something like an Ender 3 V2 (affiliate link) which has much larger community support. I have a lot of technical experience setting up machines for accuracy and can read code/program software. If you're someone like me, this is a good route to take and should reward you with a good foundation to build a fast reliable and accurate machine. If you're ready to take the red pill and join me, please continue reading my blog series.

Affiliate links

I'm not paid to promote any of these products, but if you'd like to support me, please use my amazon affiliate links below. You don't even need to purchase the item listed. As long as you purchase something after using the link, I will get something out of it. Also note that using the link does not change how much you pay (no cost to you).

• Two Trees Sapphire Plus Core XY 300300350mm Printing Size 3D Printer with Full Metal Body/Double Linear Guide/BMG Extruder/Power Resume/Filament Detect/Auto Leveling DIY 3D Printer Kit
• Creality Official Ender 3 V2 3D Printer with Upgraded Silent Main Board Carborundum Glass Platform MeanWell Power Supply, Resume Printing 220x220x250mm

3D Printing - Having an Opinionated way of doing things

 In land of consumer grade (read cheap) 3d printers, there's quite a lot of information and while it's fairly good and accurate, being objective about the information given will lead many down the road of bad choices based on their previous (possibly good) choices.

To give some context a lot of this technology is a potpourri of tech from all over the place. It comes from 3d printer companies, open source developers, and component hardware companies from both the west and the east. Each one adding new features all the time. So when you get your 3d printer, and assuming you want to get the most out of it, you'll have to pick and and choose which features from which components you will leverage. This task becomes monumentally huge when you consider how the various bits of hardware and software play together (and more importantly when they don't play together).

Most content I find on Youtube and the web tends to be objective on this matter. They will go through all the features of whatever component they are reviewing, but that doesn't really help the common 3d printer user that has a particular machine, setup a particular way, used in their particular workflow.

I will try to document my highly opinionated 3d printer journey and explain the reasons for the choices I made so that others can gain a better context of how they should setup and use their printers.