hot-end-thermal-management
|
hot-end-thermal-management [2012/12/12 18:41] jit |
hot-end-thermal-management [2013/04/04 05:13] (current) buildrob |
||
|---|---|---|---|
| Line 14: | Line 14: | ||
| The brown insulator in the middle is the thermal boundary. The part below it is to be kept hot. The part above it is to be kept cool. | The brown insulator in the middle is the thermal boundary. The part below it is to be kept hot. The part above it is to be kept cool. | ||
| - | Don't allow the air flow from the fan to hit the part below. Any part of it. | + | Don't allow the air flow from the fan to hit the part below. Any part of it. (But if the thermal barrier overheats, you may have to modify this policy.) |
| The part above, on the other hand, must be kept cool, so hit that with the airflow. | The part above, on the other hand, must be kept cool, so hit that with the airflow. | ||
| - | (Note that the fan mount can be mounted in two different positions, and this will change the air flow.) | + | (Note that the fan mount can be mounted in various different positions, and this will change the air flow. The latest model of the fan mount can be mounted in three different positions.) |
| You need to construct somehow a thing that will keep the airflow where it is needed, and away from where it is not. (Polyimide tape applied to the bottom surface of the multi-lobed aluminum part right above the thermal boundary would be a good place to start, although that alone is probably not enough.) | You need to construct somehow a thing that will keep the airflow where it is needed, and away from where it is not. (Polyimide tape applied to the bottom surface of the multi-lobed aluminum part right above the thermal boundary would be a good place to start, although that alone is probably not enough.) | ||
| Line 26: | Line 26: | ||
| Hot air rises, so a box open on the bottom but closed on the top can contain it. Construct such a box, out of materials that can withstand the high temperatures. Polyimide tape is provided, but you could use additional materials. Obviously, you must provide a way for those four wires to escape from the box, without letting too much air leak through. | Hot air rises, so a box open on the bottom but closed on the top can contain it. Construct such a box, out of materials that can withstand the high temperatures. Polyimide tape is provided, but you could use additional materials. Obviously, you must provide a way for those four wires to escape from the box, without letting too much air leak through. | ||
| - | Just putting some tape around the heater block (the rectangular part near the bottom) may not fully solve the problem, as the metal cylindrical part will also leak heat. | + | Just putting some tape around the heater block (the rectangular part near the bottom) may not fully solve the problem. |
| There is some concern that completely enclosing all of the metal parts below the thermal boundary may cause the brown insulator at the boundary to overheat. | There is some concern that completely enclosing all of the metal parts below the thermal boundary may cause the brown insulator at the boundary to overheat. | ||
| Line 53: | Line 53: | ||
| Check that the spade lugs are solidly crimped onto the cable that connects the power supply to the controller. Check the power supply voltage at the power supply screw terminals (-V to +V) and at the controller screw terminals; they should be nearly the same even when the extruder is being heated. | Check that the spade lugs are solidly crimped onto the cable that connects the power supply to the controller. Check the power supply voltage at the power supply screw terminals (-V to +V) and at the controller screw terminals; they should be nearly the same even when the extruder is being heated. | ||
| + | === one way of insulating the hot-end === | ||
| + | |||
| + | Insulating the underside of the heated platform didn't use up all the insulating fabric material, so the remainder is used for the hot end. The paper backing is peeled off, and the fabric put down sticky side up: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend1.png}} | ||
| + | |||
| + | The adhesive on the fabric will not be used to stick the material to the hot end, as that would make it difficult to remove. | ||
| + | |||
| + | The sticky side has been covered with polyimide tape, with the tape extending off the edges: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend2.png}} | ||
| + | |||
| + | Turning it over, fold the tape over: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend3.png}} | ||
| + | |||
| + | Both sides have been covered with tape: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend4.png}} | ||
| + | |||
| + | Start chopping it up. Sections to be cut out are marked with a suitable writing instrument; pencil works poorly, as do many kinds of pen. Here, a fine-tip black permanent marker was used. After each cut, the marks are wiped off with alcohol; if not removed now, they may burn off in an undesirable way the first time the hot end is heated. Alternatively, draw cutting lines on the backing paper and then cut the pieces before removing the backing paper. | ||
| + | |||
| + | After each cut, and after the ink is removed, more tape is used to seal off the cut edges: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend5.png}} | ||
| + | |||
| + | One strip 19mm wide is made, and one 14mm wide. | ||
| + | |||
| + | More cutting, resulting in two pieces: 74 x 14 mm, and 45 x 19 mm. | ||
| + | |||
| + | {{wiki:jitsbuild:hotend6.png}} | ||
| + | |||
| + | If you need to insulate two extruders from the initial 75mm strip you should cut the 19mm strip in half so that you have a 37 x 19mm (x 2 pieces) and a 75 x 14mm (x 2 pieces). In this case the 19mm piece won't be long enough to cut a full 10mm hole as described below but you will still be able to create a perfectly functional cover. | ||
| + | |||
| + | A hole is cut. It is 10mm in diameter, with its center 7 mm from one end. It should be centered along the centerline, better than this: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend7.png}} | ||
| + | |||
| + | Put it on top of the heater block: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend8.png}} | ||
| + | |||
| + | Narrow pieces of tape hold it in place as it is folded over the end of the block and underneath it: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend9.png}} | ||
| + | |||
| + | The remaining 14mm piece is wrapped around the three uncovered sides of the block, and taped in place. Additional layers of tape are wrapped around in various directions, taking care to keep the tape off the conical nozzle. None of the tape or insulating fabric should extend below the bottom of the nozzle: | ||
| + | |||
| + | {{wiki:jitsbuild:hotend10.png}} | ||
| + | |||
| + | Looks like rubbish, but it insulates the heater block fairly well. | ||
| + | |||
| + | Another alternative to taping the 19mm piece of material to the heater block itself is to instead tape it to the other 14mm strip. The position of the 19mm piece in this option is adjusted so that it extends down the side of the heater block to match the width of the 14mm skirt (which is put around the other three sides as described above). This should give the appearance of a continuous skirt all the way around the heater block which is subjectively slightly neater looking. The bottom of the heater was left open primarily again for aesthetic reasons (the cooling fan won't reach the bottom and heater block is now insulated on all the other sides). However if you are using a PLA cooling fan then you might consider covering the bottom side as well as there is a lot more indirect airflow. | ||
| + | |||
| + | {{:buildrob_hot_end_thermal_management_1.jpg?400}} {{:buildrob_hot_end_thermal_management_2.jpg?400}} | ||
| + | |||
| + | The threaded tube above the heater block is left uncovered, so it can be cooled. If it were covered, the thermal barrier (the brown material above it) would probably overheat and leak molten plastic. | ||
| + | |||
| + | It should also be remembered that the importance of such insulation is relative to the hot-end temperature you are trying to reach and the ambient temperature of the room. If you bought a PLA-only Bukobot then because much lower temperatures are required by PLA, thus far less insulation & shielding is needed, that is, ceramic tape based insulation is likely to be overkill. Simply wrapping some Kapton tape around the heater block and managing air flow from the cooling fan is likely to be sufficient - that seems to be how many other people deal with the problem. | ||
| //The contents of this page may be re-used under any of the following licenses: The [[http://creativecommons.org/licenses/by-sa/3.0/|Creative Commons Attribution-ShareAlike 3.0 Unported License (CC BY-SA 3.0)]], or the [[http://www.gnu.org/copyleft/fdl.html|GNU Free Documentation License (GFDL, version 1.2 or later)]].// | //The contents of this page may be re-used under any of the following licenses: The [[http://creativecommons.org/licenses/by-sa/3.0/|Creative Commons Attribution-ShareAlike 3.0 Unported License (CC BY-SA 3.0)]], or the [[http://www.gnu.org/copyleft/fdl.html|GNU Free Documentation License (GFDL, version 1.2 or later)]].// | ||
hot-end-thermal-management.1355359261.txt.gz · Last modified: 2012/12/12 18:41 by jit
Page Tools
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Share Alike 3.0 Unported
