Topwork thin wall mould features

The thin wall moulds we made covers:

Thin Wall Bowl Mould	Thin Wall Cup Mould	Thin Wall Packaging Mould	Thin Wall Container Mould
Thin Wall Plate Mould	Thin Wall Cup Mould	Thin Wall Fork Mould	Thin Wall Tableware Mould

• For aggressive thin-wall applications, we use steel harder than P20, especially when high wear and erosion are expected. H-13 and S136,DIN1.2316 steels have been successful in gate inserts
• Mold interlocks sometimes can stave off flexing and misalignment. so we use thin wall mould's cores to telescope into the cavity ,which can help reduce core shifting and breakage.
• We use heavier support plates (often 50 to 75 mm thick) with support pillars (typically preloaded 0.12 mm.) under the cavities and sprue. Use more and larger ejector pins than with conventional molds to reduce pin pushing.
• Strategic placement of sleeve and blade knockouts are used by us.
• No. 2 diamond polish on cores and ribs can eliminate problems of part sticking. thin wall mould's surface treatments, such as nickel-PTFE can also improve part release.
• Venting is critical and can be facilitated with vented core pins and ejector pins, as well as venting along up to 28% of the parting line around the part. Vents are typically 0.02 to 0.03 mm. deep and 5 to 1mm wide. While not usually necessary, some processors have sealed the parting line with an O-ring in order to pull a vacuum on the cavity for quick gas evacuation.
• With higher injection speeds, gates larger than the nominal walls help reduce material shear and gate wear and help prevent freeze-off before good packing is achieved.
• Gate inserts with a Rockwell (Rc) hardness greater than 55 are typically used to withstand high injection pressures.
• When gating directly onto a thin wall with a sprue, pinpoint, or hot-drop, use gate wells to reduce stress at the gate, aid filling, and reduce part damage when degating from thin wall mould.
• Hot manifolds can help reduce pressure loss in runner systems, but they require at least 0.5-in.-diam. inner passages with no sharp corners or dead zones. Manifolds should have external, not internal, heaters. Valve gates, if used, must be non-restrictive and built to take high pressure.
• .In addition, cooling of the cores and cavities is more critical and challenging in thin-wall applications. Two important guidelines adopted are: Non-looping cooling lines should usually be located directly in the core and cavity blocks to help keep the mold surface temperature as consistent as possible. Instead of decreasing coolant temperature to maintain the desired steel temperature, it is generally better to increase the amount of coolant flow through the thin wall mould. As a rule of thumb, the difference in temperature between the delivery coolant and return coolant should be no more than 5° to 10° F.
  
  

  STANDARD VS. THIN-WALL PROCESSING
  Key Factors	Conventional	Thin-Wall
  Typical Wall, in.	0.080-0.120	0.050-0.080	<0.050
  Machinery	Standard	High-end	Custom
  Inject. Pressure, psi	9000-14,000	16,000-20,000	20,000-35,000
  Hydraulic System	Standard	Standard	Accumulators on injection & clamp units. Servo valves.
  Control System	Standard	Closed-loop on injection speed, hold pressure, decompression speed, screw rpm, backpressure, and all temperatures.	Same as at left, with resolution of 0.40 in. on speed, 14.5 psi on pressure, 0.004 in. on position, 0.01 sec on time, 1 rpm on rotation, 0.10 ton on clamp force, 2° F on temperature.
  Processing
  Fill Time, sec	>2	1-2	0.1-1
  Cycle Time, sec	40-60	20-40	6-20
  plastic mold	Standard	Better venting, heavier construction, more ejector pins, better polish	Extreme venting, very heavy construction, mold interlocks, precise surface preparation, extensive ejection features, mold costs 30-40% higher than standard.