When one thinks of packaging a hundred images come to mind. It’s a huge and continually growing industry, especially in the plastics sector where PET has become king and companies are finding it more cost-effective to produce packaging using plastic rather than aluminium, glass or paper, for example.
Thanks to the technology of an in-mould labelling process it is now possible to show the texture of your favourite ice cream in razor-sharp photo quality on a moulded polypropylene package. With other striking and powerful colours, including the smooth design lines of the packaging, the product stands out amongst the rest on the shelf and catches the consumer’s attention and is bound to trigger a purchase. Every brand manager, in consultation with many others who are involved in getting the product onto the shelf, is hoping to have the same result with their product. But before you even consider matters such as taste, texture, price or shelf life, attention must be paid to the design and manufacturing of the packaging.
REH Engineering thrives on making aluminium metal chips
Six years ago REH Engineering acquired a client who needed moulds done for the treads on tyres
Packaging of product plays a big role in all aspects our daily lives. None more so than in what we eat and drink every day. Packaging is drawing even more attention these days with the world’s focus on seeking ways in which industry can tackle plastic waste, how we can decrease plastic pollution and cut down on single-use plastics. The task is mammoth especially as I can’t imagine purchasing my ice cream in any other packaging unless there is the will to return to glass packaging.
Either way, at the beginning of the chain is the engineering shop that is involved in the manufacture of the mould that is used in the mass manufacture of the packaging of the individual product.
Mould manufacturing companies, in many ways, are representative of the breadth of metalworking skills and operations. In most cases, they have one chance to get the job right and must work their magic under increasingly tough time constraints.
A typical mould shop deals with milling, drilling, jig boring, turning, grinding, EDM and heat treating to name a few of the operations required to manufacture cores and cavities. Each job that comes through the shop is different, requiring constant analysis of the shop’s capabilities with little or no benchmark from which to evaluate.
Typically, a shop looks at these operations as individual steps along the mould production line. Work flows through the shop from operation to operation in pretty much linear fashion. Some jobs need all of the shop’s capabilities while another may only require a fraction of what’s available.
In this manufacturing model, automation, to any significant degree, is generally considered too restrictive to the workflow flexibility. The shop needs to keep itself operationally agile as the clients that it is dealing with are demanding and they don’t like to wait once they make a decision on a new design for their product.
Half of REH Engineering’s machining time is taken up with general engineering machining
In February 2019 REH Engineering purchased a Feeler VFP -1300A mill from Craft Machine Tools
“Our customers are companies that don’t like to wait. Once they make a decision on a new design for one of their packages, they want to start cranking them out as soon as possible. If we can’t get good moulds to them in a timely way, someone else will. It’s that simple,” says Lee Harding, a Director at REH Engineering.
The moulds that REH manufactures are not the multi-cavity type with many cores and cavities in a single set; however their customers still want precisely machined moulds plus the extras such as finishing, moulds that deliver superior performance, tight seals and exceptional clarity.
“One industry that must always reinvent its products is packaging – specifically moulded plastic components that act as a carrier and dispenser. A significant portion of the packaging industry supports products that are relatively unaffected by a down economy. Lotions, soaps, beverages, medicines, hair care products and cleaning agents, are a few examples. Consumers have been trained by decades of advertising to associate value with changes, especially those that impact functionality and ease-of-use, in packaging design,” continued Harding.
Vacuum formed packaging
“Most of the packaging for this type of product requires a multi-cavity mould that is used on an injection moulding machine and thousands of items are pumped out. However, there are other types of plastic packaging that is ideally suited for fresh food and vegetables and manufactured via a different process, but still requires a mould. Again, thousands of the containers can be manufactured in a single shift but the method used is vacuum forming and this is the area of the packaging industry that we are involved in.”
“It only makes up 25% of our production schedule but it is an important market that we have been involved in for a number of years.”
REH Engineering has a number of other CNC machines at their disposal
Last year REH Engineering purchased a Feeler FV-1600A CNC mill from Craft Machine Tools
“Thermoformed packaging is a complicated discipline that requires a great deal of understanding of materials, and the actual methods used to create the package. Plastic vacuum forming is one of the most simplified of these methods. This process generally mimics many of the thermoforming principles, with potential cost saving measures for the client.
Vacuum formed packaging is created by stretching a heated plastic sheet over a mould. This mould has been created to resemble the item to be packaged. Then vacuum is applied to press the sheet to the mould. Because the plastic sheet is heated, it’s pliable which allows it to form to the shape of the mould. Nevertheless, vacuum formed packaging is mainly used for items shallow in depth.
The benefits of vacuum forming
Overall the costs of vacuum forming are typically lower compared to a full thermoforming packaging process that utilises plug assists. The cost of plastics is lower because of using single surface moulds as well as thinner gauge plastics. Likewise, the costs of machinery are reduced because of the simplicity of the production process. The packaging does not require as much detail and therefore allows for faster cycle times in most cases.
“There are some drawbacks to vacuum forming but the process is simpler in production and cheaper in costs for machinery and materials.”
“The company was established in 1996 as a general engineering job shop by my dad Russell Harding. He had previously started another company before selling it. Not satisfied with his ‘early retirement’ – he had sold the company when he was only 35 – he soon had to get back into creating metal chips.”
REH Engineering has been manufacturing vacuum forming moulds virtually since inception
REH Engineering also machines polyurethane components for clients
“I have been involved with the company virtually from the beginning, and when I left school I did my fitter and turning training and joined the company full time in 1999. My dad is also a fitter and turner so he was the best mentor a son could have.”
“Within five years of its establishment the company had grown to such an extent that we had to find new premises. Instead of renting we built our own factory here in Anderbolt, Boksburg and have remained here. Over the years we have added on here and there but we are comfortable in our 1 200m² space and still have room to expand.”
“It was only 12 years ago that we purchased our first CNC machine, which was a machining center that we imported from Taiwan. Obviously we can’t do without them now and we now have seven CNC machining centers, three of them with a 4th axis facility, and five CNC lathes.”
“Last year we purchased a Feeler FV-1600A CNC mill from Craft Machine Tools that has XYZ travels of 1 600mm by 800mm by 800mm, a table height from the floor of 100mm to 900mm, a table centre to column surface of 850mm, a 11kW spindle motor, XY rapid traverse of 18m/m and Z rapid traverse of 15m/m.”
“This is the biggest CNC machining center that we have purchased and it was soon followed by another Feeler. In February 2019 we purchased a Feeler VFP -1300A mill, also from Craft Machine Tools, that has XYZ travels of 1 300mm by 610mm by 560mm, a table size of 1 420mm to 600mm, a 15kW spindle motor, X rapid traverse of 32m/m and YZ rapid traverse of 24m/m.”
A general view of the machine shop at REH Engineering
REH Engineering also machines components such as barrels, rods and connectors for the mining and water purification industries and a large number of various components for the earth moving and trucking industries. Components used for hydraulic products also make up a significant portion of the company’s general engineering machining section
“We also have two slotters and a number of different conventional machines that we make use of. We don’t need an EDM wire cutting machine because as I have said we are not manufacturing the multi-cavity moulds for the injection moulding machines.”
“All of the vacuum forming moulds that we produce are machined from aluminium billet and most of our machining work is shaping aluminium, although we are very adept at machining other materials including steel, stainless steel, copper, brass and polyurethanes.”
“The company has been manufacturing vacuum forming moulds for most of the time that it has been in existence. However, we have seen many tool shops suffer from servicing just one industry. The danger of becoming so specialised is being buried with work when the market is good, forcing one to ignore opportunities from new customers in different business areas, or drying up entirely when sales are slow for an extended period of time. Much like your personal investment portfolio, diversification is the key to evening out the cycles all businesses go through.”
“Six years ago we acquired a client who needed moulds done for the treads on tyres. Uncured (or “green”) tyres consist of layers of inner liners, tyre cord fabrics, steel, Kevlar and extruded rubber. The green tyres are placed into a press where the upper and lower mould sections meet. Heat energy creates chemical reactions to cure and bind the rubber and fabric layers. Meanwhile, pneumatic bladders inflate to expand the tyre against the mould and impart the tread design and required sidewall engraving,” explained Harding.
“Traditionally the moulds used are castings. We decided to go the direct machining route. We don’t have a foundry, and we couldn’t control our costs with outside suppliers, so we came up with the solution of machining from billet stock. Although direct-machining techniques debuted in the 1960s, the process was complex, time-consuming and expensive. The advent of CNC machine tools, new age cutting tools and 3D CAD models excited many, but significantly they attacked lead times, machining times and finishes, significantly lowering costs while at the same time increasing quality and accuracies.”
“There are different style and size tyre moulds that we manufacture but typically it could take up to six weeks to produce one mould. It now forms about 25% of our business which puts us firmly in the diversification bracket.”
“The rest of our production time is taken up with machining general engineering components. These include components such as barrels, rods and connectors for the mining and water purification industries and a large number of various components for the earth moving and trucking industries.”
“Components used for hydraulic products are also a significant portion of our general engineering machining side.”
Most of REH Engineering’s machining work is shaping aluminium, although they are very adept at machining other materials including steel, stainless steel, copper, brass and polyurethanes
Warren Pretorius, Russell and Lee Harding and Pierre Schonken
“We are able to offer a design service but most of the time we are supplied with drawings. We have a high-end designing software package and where necessary we will make use of it. Currently we have an example where a new client has approached us to manufacture a new mould for him, which needs to be a bigger version of the current model. We will design and manufacture the mould for him but if we exceed our capabilities we will call on outside help.”
There is one overriding truth in the markets served by REH Engineering. Time to market is the prime directive for participation. It would be difficult, if not impossible, for a tool shop who has limited or no experience building high-cavitation/tight-tolerance/low-cycle time moulds to break into the business. Guarantees of delivery and cycle time are the norm. Knocking on the door of the big retailers and asking to become part of their RFQ list is not likely to be effective. Trying to buy your way in through significant price reductions is too risky for you and them. Finding a niche in a lower-volume speciality application, as REH Engineering has done for 50% of its business, is more likely to yield results.
For further details contact REH Engineering on TEL: 011 892 1326 or visit www.rehcnc.co.za