QUIET SOLUTION

THE SOLUTION TO THIS DAMN PROBLEM IS REALLY VERY SIMPLE, EFFECTIVE AND REALLY NEARLY COST FREE.

IN PRACTICE IS ENOUGH ALIGN AND GUIDE THE NOZZLE AND HEAT BREAKER WITH A CALIBRATED PIN BEFORE THEIR SCREWING ON THE HEATING BLOCK.

IN DETAIL IT’S SUFFICIENT, AFTER SCREWING THE HEAT BREAKER ON THE HEATING BLOCK, TO INSERT A 1.95MM CALIBRATED PIN IN ITS HOLE AND USE IT, BEFORE SCREWING THE NOZZLE, AS A GUIDE PLUG.

ONCE ALSO SCREWED UP THE NOZZLE AND PERFORMED THE USUAL ADJUSTMENTS, IT WILL BE ENOUGH TO EXTRACT (SOMETIMES EVEN WITH A LIGHT FATIGUE WITH THE AID OF A SMALL CALIPER) THE 1.95MM CALIBRATED PIN TO HAVE A PERFECT ASSEMBLY ABLE TO COMPLETELY ELIMINATE ALL CLOGGING PROBLEMS OF BOTH THE NOZZLE AND THE HEAT BREAKER AND ENSURE A PRINTING PROCESS WITHOUT INTERRUPTIONS AND OF EXCELLENT QUALITY.

IT WILL ALSO BE NOTED THAT THE NOZZLE TIGHTENING TORQUE, NOT HAVING TO COMPENSATE PARASITE TORQUES, WILL BE MUCH LOWER AND MUCH MORE IMMEDIATE TO REACH.

DIFFERENTLY FROM FIG. 4, THE PERFECT ‘COLLINEARITY’ OF THE AX EXTRUSION AX, WILL ALSO ENSURE VERY PRECISE TOLERANCES ON THE PRINTED PARTS.

ASSEMBLY WITH CALIBRATED PIN AS IN FIG. 5 AND FIG. 6:

IN FIG. 6 IS POSSIBLE UNDERSTAND HOW THE TORQUE Fn x A –  Fh x A1  IS COMPENSATED BY THE SHEAR FORCE T ABSORBED BY THE STIFFNESS AND RESISTANCE OF THE CALIBRATED PIN.

THIS EVEN FOR CONDITIONS OF VERY HIGH COEFFICIENT OF FRICTION BETWEEN THREADED PARTS (HIGH THERMAL CONDUCTIVITY ALUMINUM ALLOYSAS THE LIKE COPPER ALLOYS, DO NOT HAVE VERY LOW FRICTION COEFFICIENTS).

IN THIS CASE THE VERY IMPORTANT CONTACT SURFACE BETWEEN THE NOZZLE AND THE HEAT BREAKER IS SUBJECT TO A CONSTANT PRESSURE ON THE WHOLE RING SECTION, ENSURING THE CORRECT PRE-TENSIONING, THE PERFECT SEALING AND, LAST, THE PERFECT COLLINEARITY ‘OF THE AX EXTRUSION AXIS AS WELL AS ITS PERFECT ALIGNMENT WITH THE NOZZLE OUTLET HOLE.

IT IS SIMPLE TO UNDERSTAND HOW, IN ADDITION TO PERFECT ASSEMBLY CONDITION, THE PROBLEM OF FORCES DISTRIBUTIONS (AND THEREFORE TEMPERATURES!) NOT UNIFORM, WHICH ARE THE FIRST CAUSE OF BOTH THE NOZZLE AND THE HEAT BREAKER CLOGGING, IS COMPLETELY ELIMINATED.

IN FIG. 7 A PRACTICAL EXAMPLE OF ASSEMBLY WITH CALIBRATED PIN

NEW HOTEND CALIBRATED PIN ASSEMBLY PROCEDURE:

1. SCREW THE HEAT BREAKER ON THE HEATED BLOCK

2. INSERT THE 1.95mm CALIBRATED PIN – WE RECOMMEND A LIGHT LUBRICATION OF ITS SURFACE WITH TEFLON OR SILICONE SPRAY

3. INSERT FULLY THE NOZZLE IN THE CALIBRATED PIN

4. SLIDE THE NOZZLE WITH THE CALIBRATED PIN INSERTED UNTIL THE HEATING BLOCK THREAD

5. SCREW THE NOZZLE ON THE HEATING BLOCK WITH THE CALIBRATED PIN INSERTED UNTIL CONTACT WITH THE HEAT BREAKER

6. USING A SCREWDRIVER INSERTED IN THE ELICTRIC RESISTANCE HOLE OF THE CALIBRATED BLOCK, TIGHTEN THE NOZZLE WITH A TUBE WRENCH, MAKING SURE TO HAVE ABOUT 0.2 MM OF SPACE FROM ITS HEXAGONAL BASE WITH RESPECT TO THE HEATING BLOCK SO AS TO BE SURE THAT CONTACT IS BETWEEN ITS UPPER SURFACE AND LOWER SURFACE OF THE HEAT BREAKER. THEIR CONTACT ON THE HEATING BLOCK MUST PASS ONLY FOR THE THREADED PARTS

7. ADJUST THE POSITION OF THE HEAT SINK AS PER RAISE3D INSTRUCTIONS.

WRONG/DANGEROUS RIGHT/SIMPLE

…..MAYBE….THE ONLY ONE FOREVER…..

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