## 1 Introduction
The use of 3D printing in industry is particularly popular with TDVs (tools, devices, and verifiers) due to the fact that they are used for specific tasks, especially in the production of prototypes and single units of immediate need [23,24]. Thus, by using additive manufacturing processes, lead times are shortened and so costs decrease. This is possible because traditionally immediate-need TDVs are manufactured using computer numerical control (CNC) machines, which increase production and maintenance costs for this section that represents manufacturing preparation for a part/sub-part [25]. TDVs used in production that are currently suitable for additive manufacturing are represented by the following categories: templates for layout/marking [26,27], positioning/assembly devices [28,29], moulds for vacuum forming [30,31], moulds for injection moulding of plastics or vulcanisation of rubber [32-34], presses for bending thin sheets [35-37], and moulds for making composite parts [38-40]. The moulds used for the production of composite parts have developed with the evolution of additive manufacturing processes and are mainly used in processes and technologies that operate at low temperatures and pressures. Given the high cost of a mould made by conventional processes, additive manufacturing processes are an alternative that reduce cost and production time due to the flexibility of parts that can be manufactured using 3D prototyping [41]. An important direction of research is the production of composite blades using different methods of manufacturing using moulds. In a recent study [42], a composite blade of the tail rotor of the IAR330 helicopter was designed and analysed using the finite element method. This blade was manufactured, at a scale of 1:3, from carbon-roving spar embedded with epoxy resin, a 3D-printed honeycomb core, and an outer skin made by hand lay-up of multiple carbon-fibre-reinforced laminae; the major advantage of manufacturing this kind of blade is the low cost. [PERSON] et al. [43] manufactured a wind turbine blade, made of carbon fibre, using the vacuum-assisted resin transfer moulding (VARTM) process and a 3D-printed mould. The main contributions of the study are the technical evaluation of the process and a cost model for 3 DP moulds for VARTM that can be used to assess the feasibility of the process. It was also observed that the 3D print tooling is less accurate compared to tools made on CNC but that there is a cost and time advantage to making tooling with 3D printing processes. The life of the 3D-printed mould is limited to 15 to 30 parts, as significant wear occurs in the manufacturing process [43]. Bell and Ingersoll Machine Tools companies partnered to additively manufacture a long vacuum trim tool used to produce rotor blades for helicopters, using a hybrid machine that combines 3D printing and 5-axis milling [44]. A partnership of the US Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL), National Renewable Energy Laboratory (NREL), Sandia National Laboratories, and private company TPI Composites demonstrated the feasibility of manufacturing wind turbine blades using 3D-printed moulds, highlighting the reduced manufacturing time and cost of these tools [45]. In this paper, the feasibility of the process of manufacturing a composite helicopter blade using a 3D-printed mould was demonstrated. To obtain the composite helicopter blade, all the necessary steps were carried out, starting from the design of the mould, 3D printing and assembly of the mould sections, and blade manufacturing; finally, a comparative study was carried out on the costs of manufacturing a 3D-printed mould and the costs of a CNC manufactured mould.