A three-roll mill has three rollers mounted on an iron frame, with their centers in a straight line. It can be installed horizontally or slightly tilted. The surfaces of the three horizontal rollers press against each other and rub at different speeds to achieve grinding. Steel rollers can be hollow for water cooling. Material is fed between the middle roller and the rear roller. The three rollers rotate in different directions, with speed increasing from rear to front, creating a strong grinding effect. After grinding, the material is scraped off by a scraper in front of the front roller.
Rollers are usually made of chilled alloy cast iron by centrifugal casting, with surface hardness of HS70 or above. The roller diameter is ground with high precision, and fineness can reach about 15 μm, producing uniform and fine high-quality products. SM405 and S260 models are used for batch production. S150 and S65 models are used for small batches or laboratory work.
We can machine custom rollers, scrapers, feed plates, and other precision parts for three-roll mills from customer drawings, for single-piece or low-volume production.
Preparation
Check whether all parts are in position and locked properly. Add lubricating oil at the points shown in the diagram and connect the power.
Adjust the front, rear, left, and right handwheels and observe whether the rollers run together normally.
Remove dirt from the roller surface: wipe with soft paper or clean cotton yarn, and loosen the feed plate knob.
Set the gap between the front and rear rollers and the middle roller to 0.5 mm, then start the power and run idle for 1 to 2 minutes.
Working procedure
After startup, set the gap between the middle and rear rollers to 0.3 mm. Tighten the feed plate. Add paste as appropriate. Visually check the coloring depth. Fine-tune the rear roller so the coloring spreads evenly over the rollers, then lock the fixing nut.
Adjust the front roller handwheel with both hands so the front roller slowly contacts the middle roller. After the front roller surface is evenly colored, lock the fixing nut. Then adjust the discharge plate angle so it presses lightly on the roller surface, and the paste discharges evenly. Check discharge uniformity and finished particle size. Continue fine-tuning the front and rear rollers until the finished particle size reaches the required value. Retract the plate scraper at the front and rear in time.
After stopping work
Remove the coating and clean in time. Wipe the rollers and related parts. Loosen the scraper and feed plate. Apply a small amount of machine oil, then cover with wax paper for protection.
Precautions
Do not bump or scratch the roller surface. Do not let metal objects or hard debris enter the running rollers.
Roller working temperature range: standard type -5°C to 100°C; heated type 20°C to 220°C.
Reference gap range between rollers during normal operation: middle and rear roller gap 0.02 to 0.25 mm; middle and front roller gap 0.01 to 0.25 mm.
Do not damage the peak angle of the baffle. Adjust the contact pressure with the roller surface properly. If contact is uneven and material overflows, scrape and repair the arc surface of the baffle.
Our custom precision component machining capability is not limited to three-roll mills. Beyond rollers, scrapers, feed plates, and handwheels, we also machine yacht precision components, RC car structural parts, medical device parts, and non-standard parts for tobacco packaging machinery, filling machinery, and printing machinery. Hansheng Automation works from customer drawings and production quantities to deliver single-piece or low-volume precision machining.
