An automatic hose cutter, was needed by of one of my customers, MTG Moltec. Part of their business is to import corrugated plastic hose, in bulk and cut it to required lengths and re-sell it. This hose is available in different diameters, ranging from 10.0mm (0.394in.) diameter to 54.5mm (2.145in.) diameter.
The hose is used as an electrical flexible conduit and was cut to length manually. A large warehouse was equipped with long tables and a lot of tape measures and knives were consumed by a large number of employees!
As well as cutting hose, it was also necessary to cut electrical wire, ranging in diameter, from 1.6mm ( 0.0625in.) to 19.05mm( 0.75in.). There are 12 different diameters and or types to be accomodated.
The hose arrived at the cutting area, loosely coiled, and the hose cutter would have to have a suitable device, to uncoil the hose and present it to the machine.
The shortest length to be considered, was 51mm(2 in.) and the longest was 13.8M (45,27ft.)
It was important that all the cuts were made in the "valley" of the corrugations, so as the hose adapters could be fitted easily.
The writer was hired by the MTG Motec as an automation consultant.
The first approach was to start an initial design process to find out the technologies required. Wire and hydraulic hose cutting machines looked promising and a manufacturer was sought, who would be prepared to modify an existing design.
Eventually, after much web surfing, three manufacturers were found and requests for quotation were issued. It can take 3 or 4 weeks to generate such a quotation, but soon all the questions from the potential suppliers were answered and the three quotations were in hand.
After much deliberation and discussion with the customer, it was decided to place an order with Marken Manufacturing.
Marken are a small U.S. supplier, who are flexible enough to be able to modify an existing design, to suit the specific requirements.
The fact that a lot of the technology was available and required minimum modification, made the engineering risk, relatively low.
The Marken PL48 Dispensing Platter was used to pay-out the flexible conduit.
Note that the centering pins are adjustable. to suit the coils of different diameters.
This photo gives a look into the heart of the automatic cutting machine.
On the left is the belt drive that pulls material form the Dispensing Platter. Next in line is the measuring wheel. This device is connected to a high speed counter and is used for measuring length.
Next we can see the pneumatic cut-off knife. Note that for cutting the larger diameter cables, this is changed for a separate hydraulic actuated knife assembly.
When these larger cables are being processed a separate motorized Reel Roller is utilized.
Change over time is designed to be at a minimum and the longest change over is from processing plastic corrugated conduit to large diameter cable. (Pneumatic knife to hydraulic knife)
As with most similar projects, the hose cutter arrived a little later than expected. The installation went quickly and soon it was processing conduit.
At the beginning, it was a challenge to maintain consistency with the length of the finished product. The technician from Marken worked diligently and soon results were acceptable. The hose cutting machine has now been in production for almost 3 years and a second machine has now joined the first!
Improvements were built into the second machine, from lessons learnt from the first. The fact that a second machine was ordered shows that this project was a success and now both systems are operating reliably.