Inventive farmer makes his own precision seed planter – using 3D-printed plastic parts
PUBLISHED: 07:02 03 November 2019 | UPDATED: 07:02 03 November 2019
An inventive Norfolk farmer has solved a machinery quandary by designing his own home-built precision seed planter – made using 3D-printed plastic parts.
Many farmers are inherent tinkerers and problem-solvers - but few would contemplate designing a completely new machine from scratch.
Yet that is exactly what Jonny Leech did when a farming problem inspired him to harness both his engineering expertise and the rapid prototyping potential of 3D printing.
His unique one-pass seed drill combines strip-till cultivation to minimise ground disturbance with a precision planting system to accurately plant seeds in uniform spacings, along with a powder fertiliser, to create the optimum yield potential for his maize crops.
Its main precision component is the set of six "singulators" which separate and meter out the seeds. These were made from plastic parts printed on a 3D printer costing just £175, meaning he could print off prototypes at will and perfect them through trial and error at virtually no added cost.
The planter was designed for the sandy, drought-prone soil on the family's farm at Little Hockham, between Thetford and Attleborough, which grows 800 acres of arable crops including maize as a feedstock for anaerobic digestion (AD) biogas plants.
Mr Leech, 26, who previously worked as a design and test engineer for machinery firm Great Plains UK in Lincolnshire, said: "I just needed something that suited my soils, my crops and my requirements.
"I did a degree in agricultural engineering and spent some time as a design engineer, so I didn't want to shell out £60,000 on a new machine to do this. I knew I could built one at a fraction of the cost. It was not so much about money-saving, it was more about alleviating risk, because 3D printing is so cheap.
"With farming, everybody tries to look at margins and find ways to do things better, to keep up with the times. While some might look at crop varieties, my interests lie in machines rather than agronomy. So that is where I try to make improvements."
His initial approach was to try to customise an existing seed drill, which involved sending computer-aided design files to a manufacturer, waiting for a part to be made and returned, and then paying the full fee again for every tweak or re-design.
"I quickly realised that as a development proposal this was not going to work as I was going to spend far too much money," he said. "I wondered if I could buy a cheap 3D printer that would allow me complete design freedom and I would not have to worry about making small tweaks and getting it right first time. The first 3D printing kit was £175. I didn't realise how affordable and how accessible it was to anyone.
"At the point I had my own printer, I thought: Why am I constraining myself to that drill when I could design a whole new precision planting system?"
The bespoke singulator uses a vacuum to draw air through holes in a rotating disc, whose speed dictates the spacing and therefore the seed rate.
"All the trial and error was in this one part, and the 3D printer meant it could go through two or three iterations a day," said Mr Leech. "If I had to pay someone to remake that part every time it would have been a non-starter.
"I went through 15-20 prototype iterations of this before starting on the metalwork. I stole mother's hoover to be the vacuum on the test rig."
Mr Leech added another larger 3D printer to speed up production of almost 200 plastic parts on the machine, and the metalwork and chassis were also custom-designed and constructed by a fabricator in Garboldisham.
The finished planter, completed just in time to drill this year's maize crop has now planted 180ha of seeds.
"Even when it was built I didn't know if I was going to need to be printing new parts overnight because they were breaking," he said. "But it went really well, and the singulator worked brilliantly. Some parts have broken, but nowhere near as many as I thought."
AWARDS FOR FARM INNOVATION
Jonny Leech's one-pass precision maize planter was a top prize-winner in a competition designed to showcase home-grown farming inventions and innovations at the Royal Norfolk Show.
In the annual contest run by the Norfolk Farm Machinery Club (Normac), he won the New Ideas category for machinery developed in farm workshops to fulfil a specific need that has perhaps not been met by conventional manufacturers.
Second place went to Trevor Johnson, with a simple memory stick designed to remind sprayer operators of their obligations in setting up their sprayers, application rates, nozzles, and record-keeping.
And the award for an idea from a Normac member went to Edward Stanford of Reymerston, for his massive log splitter, built to split whole tree trunks and large limbs before cross-cutting them into a suitable size for feeding into his biomass boiler.
Meanwhile, the Innovations competition, for commercial manufacturers of farm machinery, went to Robert Crawford from Lincolnshire, showing the "Plant Tape" system of rearing and transplanting salad and green crops.