Should I put rubber gasket seals around the doors to make the enclosure more airtight?
Will having the gaps around the doors affect print adhesion depending on filament types?
v/r,
CommMan2000
Some guy did a test versus a printer with sealed doors (the Bambu maybe�) on Youtube when the J1 was out fresh and measured the achievable temperature. If I remember correctly, the J1 did quite well without sealing.
You donât want to seal off a pressure chamber in this case but rather just want to limit the exchange of the warm air inside the printer, caused by its slightly lower density. Thus, my stomach says that seals might look nice, but they are technically not needed or might be even counterproductive since the heat bed will continue heating the chamber throughout the print, regardless which chamber temperature the printer has.
That was as very good explanation. Since this is going to be my very first printer, i just want to make sure that I donât have failures for unnecessary reasons⊠like air flow. Thanks Mechanikus!
Ideal chamber temp for ABS is around 70c. I doubt that sealing the doors would cause the temp to reach those levels. So I think it could be a good idea to seal them, as long as the motors and electonics dont overheatâŠ
That should be easy enough to test: place a suitable thermometer in there (the hotend temperature sensors are probably not very precise at such relatively low temperatures if I look at the temp sensor curve in the firmware data), close the doors, power up the heat bed and wait 
Then, if necessary, temporarily close the slids in the doors with some duct tape and repeat the process.
Then you can decide based on your own observations if designing and printing additional seals might be worth the hassle.
What material are you planning to print with, as it makes a big difference?
For PLA, it would be totally unnecessary and actually counterproductive. You want to let in a lot of cool air, not prevent it. That is why it is recommended to remove the top cover from the J1 when using PLA.
With Nylons, the printer is already sealed well enough to maintain a stable internal temperature and prevent drafts.
I did use some 10mm gray weather stripping around the doors. Self adhesive so it took maybe 10 minutes to install. I measured temps before and after using a separate temperature probe. The bed was @ 100C, positioned @ Z+100mm, with the left hot-end set to 220C, and ambient room temp of 21C. Measurements were taken near the X-axis gantry height. After 30 minutes, the chamber temp reached 41C before, and 46C after adding the weather stripping. That 5C isnât likely to make a big difference, but it really depends on the material and your ambient room temp.
There was still the gap in the middle between the two doors, but also a lot of the thermal energy is being transferred through the aluminum top. It gets quite warm during long prints. Insulating the underside of the top would probably help some. I suspect if you sealed all the cracks and insulated the top, you could hit 50C. Whether of not itâs worth the trouble is up to you and what you like to print.
3 Likes
Always glad to hear another perspective. I like the idea of adding insulation to the top. My office is in the basement of our houseâŠso itâs not too hot during the summer. But, I donât need any extra heat. I will have to test temperatures to see if my J1s will make a difference. Especially, since I plan to mount it on my desk!.
When Iâm printing ABS with only the left extruder, the bed temp at 100 degrees, the right extruder reaches 54 degrees.
So some improvement would be welcome. But I did not try anything yet. Next time I print ASA or ABS I might give it a try.
I have printed top panel raiser for my Snapmaker J1(s) in size of 70 mm with ABS. Had lot of warping problems and started to think about sealing the doors and isolating the side panels and top panel.
Prints were long, up to 10 hours (dual color print of front side with Snapmaker logo). I saw the temperature rise in the chamber to max 51 C while I have heated bed only to 85 C. I have tried to print ABS with higher temperatures up to 95 C, but wrapping was even worse, so I have lowered it to 85.
I also tried to put cover around the printer, just a simple box. I saw that temperatures inside rise to 65 degree and the printing of ABS was very good. But I had some problems as heat was not evenly distributed in the chamber, prints were delaminating (cracking) if printing bed was lowered too quickly and doors opened straight after printing is finished (always in the rush).
I have one thermometer fixed at the top left corner of the door, around 50 mm away from printing bed at the top position. Second thermometer is laying at the bottom left corner of chamber 50 mm away from print bed at the lowest (home) position. So, I have two temperature reading all the time. I can compare the readings at different parts of the chamber, lower and upper part, and compare with extruder reading, if printing with only one extruder at the time. I would say extruder reading is quite accurate, difference is up to 5 degrees only, showing larger temperature, as extruder is all the time closer to heated print bed.
During the PLA printing the temperature in the chamber is evenly distributed due to the fans, both print part cooling and print cooling (auxiliary fan installed at the back panel, so actually I have J1s model 
) mixing the heated air inside the chamber. The stable temperature is in the range of 28-45 C depending on the size of the print.
Now I am waiting for additional heat source to put in the chamber and have stable temperature inside. I have ordered simple âcabinet PTC electric heaterâ with controller to keep temperature up to 75 C. I plan to install it along with additional air circulation fan (simple low constant speed fan from my Ender 3) to mix heated air inside the chamber.
Have anybody tried this already?
P.S. I will try the top panel (lid) insulation. This is definetely good idea. It does gets very warm during long prints.
Iâve done testing with the J1 and a temperature probe and the inside can reach up to almost 60°C when the bed is at 90 and the doors and top are closed. The door doesnât let too much air come through, however the temperature is higher towards the rear of the machine so there could be some merit to sealing the doors a little more
I have made some tests. The temperature reading taken from two probes (see photo) - âT1â lower at the bottom ca 50 mm from door in the left corner and âT2â upper ca 70-90 mm from left extruder at the home position. The third reading âT3â is from right extruder.
The testing was done by heating the left extruder at home position to 230 C and print bed to 65 C at the height of 200 mm from the bottom (ca 10 mm down from extruders). There was no printing (!), so no movement in the chamber. The extruder motors were switched âONâ.
The graph shows the temperature rise during ca 165 min heating. I can see that temperature will not rise anymore, at least not drastically. So, the conclusions:
- maximum temperature achieved (left extruder 230 C at home position, print bed 65 C, print bed at height 200 mm from bottom) in the chamber (upper part) is 40,5 C;
- the chamber lower and upper parts temperatures differs by 7,5 C;
- the second extruder (right) temperature reading is higher (differ by) than chamber temperature reading by 7,5 C.
The second part of the testing (and right part of graph) related to use of additional heater (75W, set to 45 C). After 170 minutes of testing (previous parameters are the same) I have added the heater into chamber. Placed it to the bottom. No fans have been used. The test was continued for 60 minutes (1 hour). Conclusions:
- the additional heater (temp 45 C) increased the chamber temperature (upper part) for 5,8 degrees and reached the maximum of 46,3 C;
- the temperature of the chamber lower part havenât increased significantly, the maximum achieved temperature is 34,2 C or increased by 1,2 C. Difference between lower and upper chamber parts temperature increased by 4,5 C and was 12,1 C;
- the right extruder temperature increased to max 55 C and was 8,7 C different from maximum chamber temperature achieved.
Have not yet tried heater higher temperatures, should be possible to go up to 70 C. Have not yet tried adding the fan (for mixing the heated air inside the chamber).
One definite conclusion is that air circulation fan is needed, as the difference between temperatures inside the chamber are to big (7,5 â 12,1 degrees). I was experiencing ABS part cracking between layers as print bed was lowering after the printing was finished. That should be the reason.
But it seems that additional heater can be helpful in case of printing ABS, ASA or more challenging filaments.
This is the photo of the temperature probes position in the printer.
2 Likes
Great investigation, thanks for sharing!
Did you also check how much using a cooling fan (or both) might change that temperature spread?
Hi,
Not yet.
But, I have noticed that during PLA printing with part cooling fan (auxiliary) âonâ the temperature distributes evenly (difference only 1-2 degrees C) inside the chamber.
This is why I made conclusion confirmed by testing results, that if even the heating of the heat bed (passive heating) is enough to achieve for example 60 C in the upper part of chamber (Miles confirmed it in the post on 23rd December), the temperature in lower part of chamber is still differ significantly. In my case difference was 12 C. I guess then the chamber temperature will rise more the temperature difference (temperature gradient) will be even larger.
The simple reasoning is that hot air will rise and dissipate throughout the top panel and unsealed doors at the top, side panels, as this part are not properly insulated. This is why the top panel insulation is definitely very good idea. I will try it soon also.
It is confirmed by my test results, but I was somewhat surprised by the fact - the temperature of the lower part of the chamber didnât changed much even after adding additional heater (!). This is definitely insulation problem, as generated heat just dissipates on its one way movement to the top of the chamber. Otherwise the convention of the air (hot air movement and mixing) will happen. It is not a case, definitely not evident here. But there are limitations. The insulation can be made from inside to have aesthetic look in case of top panel, so it is only up to 20 mm of insulation can be used (I have installed top panel riser by 70 mm using printed additional âwallsâ). It is even not possible in case of acrylic side panels and doors. I do not want to cover them, I want to see what happening inside of the printer.
This is why additional air mixing fan is needed. If placed at the upper part of the chamber the additional fan will âcut offâ the hot air movement upwards and direct it to the sides and hopefully downwards. This would allow to efficiently mix air inside the chamber, not âwastingâ heated air.
The CFD would definitely help here, but I just do not have time for that. Would be nice if someone would take effort and except challenge
My aim is to achieve 65-70 C in the chamber to be evenly distributed and mimic the actively heated chamber.
I guess it can be valuable idea for Snapmaker for further Snapmaker J1/J1s developments - to consider possibility of adding additional fan and heaters for actively heated chamber control. I see that this thing can be âeasilyâ solved even for already produced printers, by adding top panel risers (additional walls) including the heating elements and fans with control unit. Something similar to the âSnapmaker J1/J1s Tophatâ solution proposed by edgett in Printables (https://www.printables.com/model/639518-snapmaker-j1j1s-tophat/comments ).