-Challenge Accepted-
At Randcastle Complete Extrusion Systems, we manufacture bench and floor model single screw extruders for laboratory, R&D, and lower output production applications. Unique features include patented compounding technology elements The Recirculator and The Elongator that operate with twin like performance. Studies show nanopowders compounded at 50,000 x, wood sheet in one step up to 40% incorporation and more. Surge suppression, a patented Randcastle process has shown gear pump pressures (plus/minus 10 psi) without the expense and trouble.
Randcastle features unique interchangeable feed sections, discharge driven screws for small extruders and conventional horizontal extruders, and a host of downstream products. We lead the industry in product turn around time, reliability, and quality. Randcastle is proud to be an active research facility. Keith Luker leads our laboratory team who are always ready for a good challenge. Contact us with your projects and we will help you sort it out. We love making science happen and are passionate about pushing the boundaries of extrusion technology. Randcastle is a company of people dedicated to creating sustainable technology that improves the world and pushes the boundaries of science. We challenge pre-conceptions and the status quo and have been moving the industry forward with creativity and innovation. We are as much a research facility as we are a manufacturer. We ensure our clients a custom product that exceeds their expectations. Our innovation sets us apart.
A letter From the President
When I started Randcastle in 1987, I didn’t know that we would become a company that could seriously claim to have advanced the state-of-the-art of extrusion. I thought that we would innovate in small extrusion lines. That worked out and we pioneered everything from proprietary feed sections to patented surge suppression to make them work better.
Looking back, I had no idea that we would supply patented after market compounding screws for over 1,000 pounds per hour that rival, sometimes exceed, what twins can do. That might be hard for you to believe but, fortunately, we have evidence. We can show you nano materials, at 100,000 times magnification, that are well distributed. We can show you sub-micron PS globules, at 5,000 times magnification (whereas some, so called, state-of-the-art single screws are still researching with optical microscopes!). We can show you compounded wood, TPO’s, and solve problems that you may not even know exist (such as reagglomeration).
Now, we’re bringing new technology on-line including:
•Micro-Batch mixers: We’re developing machinery to replace the cumbersome lab batch mixers that you’re used to. You won’t have to scrape hot material off rotors into a messy pile, then grind that pile and then try to mold the grindings. Instead, you’ll take 100 grams of ingredients (your batch size), melt, mix and then extrude directly into a strand. Very shortly, we plan on equipment that will go one step further: In 15 minutes, you’ll go from your 100 grams batch of raw ingredients to a tensile bar.
•Injection Molding Screws: We’re installing our first molding screw. We expect to show serious property improvement.
•Direct Extrusion: We’re already compounding directly into product at the lab scale but as this technology blossoms, the advantages of single screw compounding will let you compound while you extrude at thousands of pound per hour—saving money while you make a better product.
•Venting: We’ve invented a new venting mechanism in the single screw extruder. It’s shorter than your typical two stage screw so we can fit three vents into a 36/1 single. And, since it mixes while it vents, we pretty sure it will vent better too. One of the nice things about this business, is that I don’t know where we’re going. But, everyone at Randcastle looks forward—because that’s our job.
Engineering Benefits
Before we built the vertical extruder, screws smaller than 1 inch broke easily and fed poorly. The solution is the “discharge driven” Microtruder. These are some of the benefits of our state of the art technology. Strong Screw*: An extruder screw must withstand the stress of feeding, melting, mixing, and pumping so Randcastle drives the screw through the metering section of the screw. The metering section root diameter is about 2 to 4 times as strong as the weak feed section root diameter allowing much smaller extruders.
Excellent Feeding:
A functional extruder gets the feed stock to the screw. In a typical extruder, there is a hole in the barrel, proportional to the screw diameter, that allows t he feed stock to enter the screw from the hopper. The hole becomes so small in these extruders under one inch that the feed stock arches (also called “bridging” and “piping”) over the hole. Once the feed becomes erratic, the extruder cannot pump uniformly. Randcastle’s vertical design extends the screw into the feed stock to solve the problem. Attachments to the rotating screw can extend into the hopper to aid in feeding particularly difficult powders and cohesive (non-free flowing) feed stocks.
Superior Compounding:
Mixing is important in most extrusion applications but critical in some. Pending patents for our Recirculator mixing elements demonstrate, in published peer reviewed papers, success in applications previously only possible with twin screw extruders including such high filler loadings as 40% wood flour and pellets directly into sheet. Improved
Melting:
Our patent pending melting technology makes better melted product at lower temperatures and higher extrusion rates.
Feeding Further Enhanced:
Randcastle pioneered unique smooth bore feed sections that can make for significantly better feeding and consequently more uniform pressures1 . These feed sections can be changed in under one minute with just four clamping screws. So often, if you select the wrong screw design for an experiment, you can simply change the feed section to solve the problem without removing the screw and cleaning it.
Uniform Pumping:
Randcastle discovered a novel method of making extruders pump better. We named this method, “Surge Suppression” and we incorporate it into every screw we make. Essentially, if you view a surge as a wave, the Surge Suppressor stores the top part of the wave and inserts the stored material into the trough of the wave. The Surge Suppressor operates automatically giving every Randcastle screw more uniform operation. Batch Size: Until the Microtruder, researchers were forced to make multiple expensive batches to make a single trial. Using the Microtruder, complete trials with as little as 10 grams of polymer are possible. Production applications, such as catheters and coextrusion, also benefit from the Microtruder. Extruders that are too large for the application degrade the polymer because the screw turns too slowly. This makes the residence time excessive and causes a loss of properties in the extrudate. The Microtruders permits normal screw speeds to prevent burning. Space Savings: The vertical design has an extremely small footprint so it is readily engineered into small spaces.
Microtruder Features & Specifications:
All standard Microtruders include the extruder and a control pane .l The standard extruder includes a 24:1 working L/D ratio 4140 hardened screw, removable water cooled feed sections made from hardened stainless steel (s.s.), a 1750 RPM DC motor, 15:1 gear reducer with integral thrust bearings and keyed drive quill, nitrided s.s. barrel with mica band heaters, s.s. barrel cover, rupture disc 1 , and a s.s. breaker plate. The standard control panel includes (3) auto tuning temperature controllers for the barrel and (1) for the die, a variable speed AC motor control with 1000:1 speed range and overload amperage protection, digital motor amme ter, and a digital screw speed readout. Bench mounting is standard and includes height and leveling adjustment (shown on the RCP -1000 below). Typical dimensions are given on page 7. Detailed assembly drawings available. Outputs in the following chart1 can be reduced by about 60% with low output screws and increased about 300% with Recirculator Technology.
Origin Story
It all began with a man and an idea. After an accelerated graduation from Montclair State University, Keith Luker knew he could create technology that would reinvent the mixing industry. Randcastle was born as a small startup in his residential garage. In the 37 years since, Keith and Randcastle Extrusion Systems now hold 5 patents, a number of prestigious speaking and teaching positions and awards, and Randcastle has become an industry leader on single screw extrusion. New evidence supported by Rutgers University and Dow Chemical have proven what Keith knew all along… Single Screw Extruders, properly equipped with Randcastle’s patented technology, are mixing exponentially better than anything in history. Randcastle mixing, pressure stability, and specialized feeding processes are the best in the industry. We are proud of that and we look forward to proving it to you.