XxxXxx Clamp XXXXXXXxx-8710

Mold Flow and Molding Pressure Analysis

Presented By: Anthony HillProject Engineer

Summary of Objectives & Goals

The primary objective of this analysis was to provide a balanced filling pattern and determine the feasibility of using Xxxxxxxxx 06E nozzles.To determine the maximum pressure through the hot runner system.Note: Occurrence numbers were used in this analysis to utilize symmetry

Objectives:

Final Conclusions:

A 8-Drop VG Xxxxxx manifold was used to fill the small part using direct gating on each part.The filling is balanced within 1% volume.Max system pressure was 9,846.8 psi. This does not include machine nozzle/barrel loss.The pressure loss of 8,959 psi in the manifold is past the Xxxxxxx Hot Runner System guidelines but was within the 60% of the machine capacity (17,400 psi) and therefore determined to be acceptable for this application.

Notes:

No Part Color change or specification other than “Black”

Part, Tool, Setup & Results Summary

Material PPS, Polyplastics FORTRON 1140A1

Material Present In Moldflow Database ? Yes

Melt Temperature 608F

Mold Temperature 302F

Fill Time .85 sec.

Velocity/Pressure Transfer (% volume) 99% Of Volume Filled

Part Name: XXXXxxxxx-8710

CAD File / Date 2049 3-D Mold Drops.XT (9/5/13)

Part Volume (Total) 2.72 in^3

Nominal Wall Thickness 3mm

Color Change ? NO

Tool Description 8-cavity, 8-drop VG Xxxxxxx manifold

Specified Clamp Tonnage Limit 150 T

Part Details and Tool Description

Process Setup

Analysis Results

Maximum Flow Rate 3.217 In^3/sec

Total System Pressure 9,893.5 psi

Clamp Tonnage Calculation 50.4 US Tons

Projected Area 13.6 in^2

Maximum Melt Front Temperature 620.4F

Minimum Melt Front Temperature 605.9F

Maximum Shear Rate 33,035 1/sec

Part Thickness

Used 3D (tetrahedral mesh) analysis

Material DataGeneral: Recommended Processing:

Rheology:

Hot Runner Specifications

Nozzle Type 06E

Tip Style Valve gate

Manifold Shape Multi-leg special

Main Manifold Bore Diameter 14mm, 12mm, 10mm and 8mm

Drop Bore Diameter 6mm

Gate Orifice Diameter 1.6mm

J dimensions About 5.6”

Part+Cold Runner Volume 2.72 in^3

Manifold Volume 6.26 in^3

Turnover (Part Vol. / Manifold Vol.) .43

Manifold Pressure Drop 8,959 psi (within molding machine capacity, 60% of max. </= 17400/29010 psi). Small part size, fast injection time and long nozzles cause high pressure loss.

The Xxxxxxxx General Assembly Drawing and Bill Of Materials provides a complete and detailed presentation of The Final, “As Built” Xxxxxxxxx Hot Runner System

Nozzle Locations & Bores

Inlet(0,0)

06 E NozzleX = 2.0”Y = 2.875”Bore = 6 mm

06 E NozzleX = 6.0”Y = 2.875”Bore = 6 mm

06 E NozzleX = 2.0”Y = -2.875”Bore = 6 mm

06 E NozzleX = 6.0”Y = -2.875”Bore = 6 mm

06 E NozzleX = -2.0”Y = -2.875”Bore = 6 mm

06 E NozzleX = -6.0”Y = -2.875”Bore = 6 mm

06 E NozzleX = -2.0”Y = 2.875”Bore = 6 mm

View From Machine Nozzle

06 E NozzleX = -6.0”Y = 2.875”Bore = 6 mm

Manifold BoresInlet(0,0)

View From Machine Nozzle

Dia. 14 mm

Dia. 12 mm

Dia. 10 mm

Dia. 8 mm

Dia. 8 mm

Level change

Filling Animation – Link to .avi File

Fill Time Contour Plot & Valve Gate Timing

This contour plot shows the flow front animation as colored contours. Each contour represents a snapshot of the flow front at an instant in time. This type of plot makes it easy to identify areas of hesitation (contours are spaced much closer than the rest of the part).

All valve gates open at same time

System Injection Pressure2nd stage Pack Pressure 9.1 sec @ 7,877 psi

This XY plot shows the pressure as seen from the hot manifold inlet (plastic pressure). It includes the pressure drop in the manifold and the pressure to fill the part(s). It does NOT include the machine barrel/nozzle pressure loss. Typical pressure loss in a machine barrel can range from 1,000 to 4,000 psi plastic pressure (depending on internal geometry and orifice size). In order to calculate the machine hydraulic pressure, the values shown on the plot needs to be divided by the machine intensification ratio.

Cavity Pressure at Switchover (99% Filled)

This plot is a snapshot of the pressure distribution in the cavity at the instant of switchover. (scale does NOT include runner system).

Cavity Pressure Distribution During Pack

This plot is a snapshot of the pressure distribution during the initial packing phase.(scale does NOT include runner system).

Flow Front Temperature

This plot shows the temperature of the polymer when the flow front reaches the specified point (taken at the center of the cross section). Flow front temperature variation should be less than 30 F.

Weld Lines & Temperature During Formation

The weld line result displays weld lines that form at a meeting angle(θ) of 135 degrees or less. The color of the weld lines shown indicates the temperature at which they formed. Lower temperatures may indicate that it will be difficult to control the appearance of the weld line. The strength of the cooler weld lines may also be less than higher temperature weld lines. The length of all weld and meld lines should be minimized. Where possible, horizontal weld and meld lines are preferred to vertical lines.

Average Fiber Orientation

The Average fiber orientation result shows the movement of fibers during the injection molding process, averaged over the thickness. The result above is a snapshot at the end of the cycle and is a good tool to look for inconsistent orientation.

Clamp Force CalculationMachine Clamp Limit 150 T

Projected Area 13.6 in^2

Max Clamp Calculated during Fill 21.5 T

Max Clamp Calculated during Pack 50.54T

The clamp force is a function of injection pressure and the projected area of the part. A good clamp force plot should show that maximum clamp force applied is less than approximately 75% of the machine limit, allowing the remaining 25% as a safety factor. Note: Clamp force requirements typically increase during pack (which is not shown in a Filling-Only analysis)

Air Traps

The areas highlighted in pink show possible air trap locations. An air trap occurs where the melt traps and compresses a bubble of air or gas between two or more converging flow fronts, or between the flow front and the cavity wall. Gas traps should be forced to the edges of the part. Gas traps located at the edges of the part should be vented. Gas traps that are on the surface of the part should be avoided. Consequences: Gas traps that are not properly vented can cause gas burns in those locations.

Shear RateMaximum Shear rate per Material Supplier 50,000 1/sec

Maximum Shear rate Calculation 33,035 1/sec

Location of Max Shear rate Gate area

The shear rate is a measure of how quickly the layers of plastic are sliding past each other. If this happens too fast, the polymer chains break and the material degrades. The bulk shear rate should not exceed the maximum value recommended by the material supplier. Exceeding this value would likely lead to polymer degradation. In cases of aesthetic applications, a good rule of thumb is not to exceed 60% of the supplier recommended value.

Volumetric Shrinkage at Ejection

The Volumetric shrinkage result shows the volumetric shrinkage for each area as a percent of the original volume. Shrinkage values should be uniform throughout the part. The target value is 3 times the tool shrinkage rate. For example, for tool that has 0.8% shrinkage, volumetric shrinkage is 0.8% * 3 = 2.4%. This is important for good packing of the material, ensuring good structural and visual integrity of the part. If the value is greater than 3 times it could lead to undesirable part warpage, and it should be evaluated in greater detail with warpage analysis.

Nominal wall varied from .19% - .45%