Cross Sword contacted RP Technologies after being recommended to use their prototype tooling & plastic injection moulding services. After initially contacting 2 different companies, both of which created more problems than solutions, Daniel Bush, founder of Cross Sword was relieved that RP listened to his needs and developed a solution to help launch his latest product.

Cross Sword develop and sell luxury high heel shoes for men that have a classic look. The company identified a lack of products for those that wish to wear masculine styled shoes with a high heel so launched the start-up company to offer a comfortable solution for the male high heel wearer.

During the product design process for the heel for their latest shoe model, Bush contacted RP Technologies to assist with the development of the tooling and plastic injection moulded components. The heel is the focus point of the product with a unique design, which after many struggles with other manufacturers, RP helped Bush to find a solution to help bring the new Cross Sword heel to production.

The Cross Sword heel is constructed from 3 plastic components: the heel block, a window and the sole.

The heel block is made from ABS which is a common material for heels in the shoe industry due to it being lightweight yet extremely durable and hard wearing. What makes Cross Sword’s heel different is that it’s been shaped to look thinner than it actually is.

The heel features a window which is manufactured from clear polycarbonate. This window has two roles, firstly to keep the heel looking thin, and secondly to showcase an encapsulated silver emblem, like a display cabinet. The solid silver jewellery piece representing the Cross Sword logo is placed into the ABS heel before the polycarbonate window is fitted in front of it.

The third part of the heel is a TPU sole which has 3 metal pins inserted moulded into it, allowing the sole to be attached to the bottom of the ABS heel. TPU was selected due to its high abrasion resistance however the insert moulded pins mean the sole is interchangeable when it eventually wears down.

Once the 3 plastic components and the silver jewellery piece are assembled, the full heel is then attached to the base of the shoe, completing the look.

When RP’s team of in-house tool designers began to design the tooling there were two issues to overcome: firstly, the thickness of the heel cross section would cause very heavy sinking when moulded and secondly, they had to be mindful that the polycarbonate window moulding could develop jetting/bloom marks if the correct gating configuration wasn’t used.

Due to the thickness of the heel component, consideration had to be given when developing the tooling. RP’s team of tool designers and process engineers discussed a few different options to find a suitable solution and develop a new process. This allowed a uniform thickness across the heel component without heavy sections causing sink marks as the moulding cools.

Cross Sword had high quality expectations for the clarity of the window component. When RP designed the tool, they had to consider the gate positioning carefully to ensure these requirements were met. After originally developing the window component in polycarbonate, a better solution was found using a PMMA grade, which gave greater clarity and a higher quality finish.

Once Cross Sword approved sample parts, RP began production of the heel, manufacturing 100 sets of components for their initial product launch.

Bush commented “using RP has been a real benefit to our product development process. The communication has been fantastic. They are very realistic in their problem solving and are open and honest when discussing the technical details. Best of all they’ve provided a solution to launch my product whilst staying within my budget.”

Cross Sword have plans to develop additional models of shoes and will be utilising RP Technologies services to bring their future products to market. Bush added “I initially contacted 2 other prototype moulding companies who made problems out of nothing and wasted a lot of my time with useless design changes, which still didn’t suit their manufacturing processes. Working with RP has been a breath of fresh air.”

Via Engineering Update