Advanced
search

Robots reach into plastics

Industrial Robot

ISSN: 0143-991x

Article publication date: 1 December 2000

51
Article view Figure view Cited (7) cite article

Keywords

Citation

(2000), "Robots reach into plastics", Industrial Robot, Vol. 27 No. 6. https://doi.org/10.1108/ir.2000.04927fab.001

Publisher

:

Emerald Group Publishing Limited

Copyright © 2000, MCB UP Limited

Robots reach into plastics

Robots reach into plastics

Keywords Plastics, Robots

Robots reach in to enable faster cycle times and better part quality for plastic moulding machine users. More than 50 companies exhibited robots at the National Plastics Exposition 2000 held recently at McCormick Place, Chicago. Robot exhibitors included independent robot producers as well as plastics moulding machine builders who also provide robotic machine unloading systems of their own design.

Plastics moulding applications require robots designed with special abilities. Payloads range down to only 2kg or 3kg. Axes of motion start with only three and range up to six or seven. Arm cross-section profiles are very narrow to minimize the distance the mould must open to permit the robot arm to start reaching in. The greater the arm cross-section, the more lost time in opening and closing, all non-productive machine time.

Most plastic machine unloading robots also feature extremely close motion co-ordination with the movements of the moulding machine. The program of the robot motion is linked with the various cycles of the plastic moulding

machine. A typical moulding cycle includes closing the mould, mould lock-up, plastic material injection, set-up or cooling time, mould unlock, moulding opening and part unloading or ejection. Traditional hydraulic-powered machines tend to operate in completely series fashion. Newer designs provide for some parallel action and new all-electric drive machines offer parallel operation wherever possible.

The robot waits at the ready very close to the mould and starts into the gap between the mould sections as soon as clearance is available. Motion of the part extraction pins is synchronised with robot motion to have vacuum cups meet parts at the optimum point. Closure of the moulds is initiated as soon as the robot arm with parts attached clears the mould. Mould closure to start the next productive cycle commences as the robot continues its travel to the part drop-off location.

Some of the exhibitors with a primary focus on plastic moulding applications include Wittmann from Austria, Sailor, Yushin and Ichikoh from Japan, Ventax Robot of Canada and Automated Assemblies, Automation Engineering, Direct-Line and Stertech of the USA. The major full line robot producers such as Fanuc, ABB and Yaskawa (Motoman) were also exhibiting and many showed special overhead rail style designs units for machine unloading.

Most of the robots are of the linear rail-mounted design necessitated by the need to operate overhead of the machines. Many of the designs employ space age material technology such as composite carbon fibre to provide maximum strength with minimum weight. The lightweight designs enable suppliers to claim unload cycle time in the sub one second range.

Fanuc introduced a new 70kg payload rail-mounted model, M-710iT, with six-axes of dexterity and a reach of 1.9m. This new unit has greater payload and greater reach than the other three models in the Toploader family of machine load/unload robots from Fanuc.

Linear drive technology is being applied to plastic robots to reduce the drive train inertia, improve acceleration performance and reduce maintenance.

Linear drives eliminate many of the maintenance concerns such as cylinders, traditional rotary motors, gearboxes, racks, pinions, belts and ballscrews.

Another robot application in the plastics industry is for part trimming and flash removal. The robot carries a water jet nozzle or a rotary deburring head which is moved rapidly along the part edge requiring trimming or de-flashing. Typical applications are clean-up of plastic automotive parts such as dashboards, bumpers and interior trim panels.

Web sites to obtain more information from the suppliers mentioned are:

Related articles

Manage cookies

All feedback is valuable

Please share your general feedback

Report an issue or find answers to frequently asked questions

Contact Customer Support