US-12623385-B2 - Mould tool, method of assembling a mould tool and method of manufacture using a mould tool

US12623385B2US 12623385 B2US12623385 B2US 12623385B2US-12623385-B2

Abstract

A mould tool ( 100 ) is provided which has a multipart mould layer assembly ( 200; 300; 400; 500; 600 ) which may either be formed from a carrier ( 202; 302; 402; 502 ) and an insert ( 206; 306; 406; 506 ) defining a mould profile, or a mould face component ( 602; 702 ) having a plurality of stackable blocks ( 630, 632, 634 ) which can be assembled to form a mould layer.

Inventors

Ben Halford

Assignees

SURFACE GENERATION LIMITED

Dates

Publication Date: 20260512
Application Date: 20240115
Priority Date: 20180212

Claims (13)

1 . A mould layer assembly comprising: a carrier defining a carrier mould contact face on a first side, and a temperature control face on a second side opposite the first, which temperature control face is separated into a plurality of tessellated temperature control zones, each zone comprising a fluid chamber at least partially defined by the temperature control face, the carrier defining an insert cavity overlapping a subset of the plurality of tessellated temperature control zones, and not overlapping a remainder of the plurality of tessellated temperature control zones, wherein the insert cavity is defined by a sidewall; and an insert defining a mould profile for forming a moulded article and an insert temperature control surface that is opposite the mould profile, the insert being disposed in the insert cavity of the carrier such that the insert overlaps the subset of the plurality of the tessellated temperature control zones and such that the insert temperature control surface is in direct thermal contact with the subset of the plurality of tessellated temperature control zones, the insert comprising an insert mould contact face adjacent the mould profile, the insert mould contact face being parallel and adjacent to the carrier mould contact face, wherein the insert does not extend past the sidewall when assembled in the insert cavity.
2 . The mould layer assembly according to claim 1 , wherein at least one of: the insert overlaps a plurality of the tessellated temperature control zones; and the mould profile overlaps a plurality of the tessellated temperature control zones.
3 . The mould layer assembly according to claim 1 , wherein the carrier comprises a support surface for supporting the insert in the insert cavity.
4 . The mould layer assembly according to claim 3 , wherein at least one of: the support surface comprises a peripheral support around the insert cavity; and the fluid chambers are defined by chamber sidewalls, and wherein the support comprises ends of the chamber sidewalls.
5 . A mould layer assembly according to claim 3 , wherein the fluid chambers contain ribs, and wherein the support surface comprises ends of the ribs.
6 . The mould layer assembly according to claim 5 , wherein chamber sidewalls form a rectangular lattice, and wherein the ribs extend at an angle to the chamber sidewalls.
7 . The mould layer assembly according to claim 5 , wherein the ribs define concave formations facing away from the insert.
8 . The mould layer assembly according to claim 7 , wherein the ribs are arch-shaped, such that a plurality of ribs extend from the chamber sidewalls to an impingement region.
9 . The mould layer assembly according to claim 1 , wherein the carrier mould contact face and the insert mould contact face are co-planar.
10 . The mould layer assembly according to claim 1 , wherein the remainder of the plurality of tessellated temperature control zones surround the subset of the plurality of tessellated temperature control zones.
11 . The mould layer assembly according to claim 1 , wherein the plurality of tessellated temperature control zones are rectangular and arranged in a grid.
12 . A mould tool comprising: a plurality of temperature control assemblies each comprising a heater; and, a mould layer assembly according to claim 1 , wherein the temperature control assemblies are controllable to individually heat each of the chambers.
13 . The mould tool according to claim 12 , wherein each of the temperature control assemblies comprises a fluid outlet directed into the respective chamber, such that at least one of: each of the temperature control assemblies is configured to alternately heat and cool a respective chamber with fluid from the outlet; and at least one of the fluid outlets is directed towards the insert.

Description

The present invention is concerned with a mould tool, a method of assembling such a mould tool and a method of manufacturing moulded parts using a mould tool. More specifically, the present invention is concerned with a mould tool having multiple parts which can be independently manufactured and assembled to form the tool such that at least some parts of the mould tool can be re-used to mould parts having different geometries. Mould tools for the heating and cooling of a part located in a mould cavity are well known. The applicant of the present application has filed prior patent applications to such tools. WO2011/048365 is directed to a tool and method of moulding in which fluid is directed at the back of a mould face to heat and cool the face, and hence the workpiece material. The tool is separated into a number of tessellated zones across the workpiece, each of which can be independently controlled to produce the workpiece according to a functional specification. WO2013/021195 is directed to a mould tool which uses the same heating and cooling principle of WO2011/048365 but is separated into a number of layers. There is a provided a mould layer which has a mould surface defined on a first side (against which the workpiece is formed) and a temperature control surface defined on the opposite side. A plurality of chambers are defined which are partially delimited by the temperature control surface. There is also provided an exhaust layer adjacent the mould layer, and a utilities layer adjacent the exhaust layer. Thermal control assemblies and thermocouples extend from the utilities layer, through the exhaust layer and into the mould layer. The thermal control assemblies direct heating and cooling air at the temperature control face of the mould layer to heat or cool it. The used air flows back into the exhaust layer and exits the tool. The thermocouples extend into contact with the temperature control surface. A controller can heat or cool each zone to match a desired temperature profile of the tool surface and therefore workpiece. WO2014/023942 is directed to a similar mould tool to WO2011/048365, and a further improvement in which arches are defined on the temperature control face. The arches are used to improve the general structural rigidity of the mould layer, to direct the impinging air flow and to direct the moulding load through to the exhaust layer. WO2014/023942, WO2013/021195 and WO2011/048365 are incorporated herein by reference where permitted. It is clear that the general requirement for mould tools described above is a multi-chamber structure defining the mould face, which is thermally agile (i.e. using as little material as possible) and has some relatively fine detail formed adjacent the temperature control face. There are two situations in which the above requirements can cause problems. The first is when a particularly fine or high precision finish is required on the mould face. For example, small, thin and light parts may require a high precision finish. The fields of medical implants, consumer electronics and optics are good examples, in which many parts are quite “flat” (i.e. pseudo 2D or “2.5D”). The moulding of e.g. plastic lenses requires a very high precision mould surface. A problem with this is that such finishes can often only be achieved with small, high precision machining tools. It is often the case that it is impractical or impossible to machine entire mould layers to such high precision over a relatively small part of the mould surface. “Flat” parts are often disproportionally disadvantaged in terms of cost. For simpler 2D or 2.5D profiles, a disproportionate amount of machining must be undertaken to the back face of the mould layer to form the arched ribs. This problem is exacerbated by low volume runs. The second is that parts which are “high depth” can be problematic. The direction in which the mould tools come together is known as the depth or “Z” direction (although it may be vertical in e.g. compression moulding, or horizontal in e.g. injection moulding). These parts therefore have a high Z-dimension- or in other words have a high aspect ratio in the depth direction. Such parts are also known as “2.5D” or “3D” (i.e. they are not very flat). The exhaust layer and utilities layer of the above-described tools are typically interchangeable with a variety of tool layers. The exhaust layer presents a flat, planar face to which the mould layer is abutted. Therefore a high-depth part requires a high-depth mould layer. This means that the chambers at the areas furthers from the exhaust layer need to be very deep. This causes problems for manufacture. Machining such a mould layer from solid is problematic because it is very wasteful (and therefore expensive), and further it is difficult to machine very deep chambers. Casting such components to full depth, although more economical is also not ideal as such shapes are not well-suited to casting, and further it is still not easy t