Resin change
High to low temperatureControlled
When old and next resins run far-apart production temperatures, one purging grade may not span the changeover. The Temperature Bridge principle uses overlapping temperature ranges as the link under a technician-confirmed plan.
Why direct temperature drops or jumps need care
Super engineering plastics like PEEK run far hotter than general resins. Dropping temperature before old resin purges out risks frozen or held material. Running high-temp compound down into low ranges may exit that grade range.
Old resin, compound and next resin may share no suitable temperature window, complicating flow, viscosity and residence-time control
Pick two grades with overlapping ranges, fixing the switch point inside from real machine data and current TDS
PX2 vs GL3 and RU overlap ranges
Current TDS lists PX2 at 280–420°C and GL3 and RU at 180–330°C, a data overlap of 280–330°C. But overlap never auto-orders a grade switch at any single temperature.
Data overlap: 280–330°C
Real switch points must come from source resin, target resin, melt temperature, machine structure and residence-time limits
Must not be used with Hot Runner
Technician-set switch point
Bridging to general resins
Plan differently by temperature-change direction
Both directions share the overlap principle, but temperature-verification order and risks differ. Examples are planning frameworks, not machine settings.
From PEEK to ABS
- Confirm the high-temp grade fits old resin and the real machine
- Purge old resin without holding compound past TDS limits
- Enter the overlap range per the technician-set plan
- Switch to verified GL3 or RU, then drop into the ABS range
- Verify real discharge before counting good parts
From ABS to PEEK
- Start with GL3 or RU fitting old resin and machine limits
- Climb temperature under continuous material purging per the site plan
- Switch to PX2 inside the technician-confirmed range
- Climb into the high-temp resin range without holding PX2
- Verify cleanliness, real temperature and part terms before production
Each grade bridge role
Overlapping ranges never mean interchangeable grades. Verify role, process, Hot Runner, Glass Fiber, sealing and clearance separately.
High-cleaning grade for super engineering plastics such as PPS, PEEK, PEI and LCP
- Contains Glass Fiber
- Must not be used with Hot Runner
- Sealing prohibited
General high-cleaning grade without Glass Fiber for general and most engineering resins
- Hot Runner compatible at 0.5 mm clearance or more
- Sealing per TDS
- Check screen packs before extrusion use
R-Series for color and material change, supporting injection, Hot Runner and extrusion per TDS limits
- Glass-fiber-free
- Hot Runner needs 0.5 mm clearance or more
- Sealing per TDS
Stop-and-check limits before temperature changes
Set machine temperatures may not equal melt temperatures, and staying in TDS ranges never permits uncontrolled compound residence
No barrel residence even briefly Per July 2021 TDS, never past the 420°C range
No barrel residence over 30 min, never past the 330°C range, per October 2023 TDS
No barrel residence over 30 min, never past the 330°C range, per March 2025 TDS
6 items to prep for technicians
Complete data fixes grade switch points, stop gates and result checks more safely than single-temperature picks
Old and next resin
Grade names, maker, color and reinforcements
Real all-zone temperatures
Nozzle, die, Hot Runner and melt temperature if any
Machine and system size
Injection or extrusion, barrel capacity and screw diameter
Flow path and screens
Hot Runner, minimum clearance, screen mesh and dead spots
Main problems
Material change, color, specks, burn or holdup
Part pass gates
Color, specks, clarity, weight, dimensions and acceptable scrap counts
Documents to verify together
Source order: Each grade current TDS, resin type and maker manual, real machine data, Controlled Trial
Legacy manuals cite GL2(U) as the bridge grade, but GL3 upgrades GL2. Real use must have technicians confirm GL3 or RU and the latest switch point every time.
What is a Temperature Bridge
Using more than one purging grade, picking grades with overlapping temperature ranges to bridge resin changes across far-apart production temperatures under a verified plan
Can PX2 switch to GL3 or RU right at 280°C
Never conclude from one figure. 280°C is only PX2 lower edge inside GL3 and RU ranges. Real switch points weigh melt temperature, resin types, machine, residence time and nozzle and die discharge.
Does this method work with Hot Runner
PX2 barred from Hot Runner. Never apply this example order to Hot Runner directly. Have technicians inspect the system and pick flow-path-fitting alternatives.
Does the overlap guarantee clean purging
No guarantee. Temperature is one term among residue amounts, resin compatibility, clearance, screen mesh, residence time and part quality gates.
Have technicians plan your machine Temperature Bridge
Send source-target resin, temperature, machine, Hot Runner and screen mesh and pass gates to plan Controlled Trials before real use