Virgilio Perez Guembe
Salesregion: South & Middle America, Europe, Asia
Frequently asked questions
Below we list the questions that our customers and interested parties are particularly interested in having answered. We have grouped these various topics under the headings of Contaminants, Parts to be cleaned, Process, Systems / Installations and Services.
Contaminants
Thermal cleaning can be used to remove all organic adhesions and contaminants from temperature-resistant, heat-resistant materials. During the thermal decomposition of organic substances such as polymers (plastics, additives), paints / varnishes, rubber or even foodstuffs, inorganic by-products or residues can be caused depending on the source material and additives, which can then be removed in an adapted post-treatment process.
SCHWING is the only manufacturer in the world capable of removing any polymer or plastic from heat-resistant metal parts without leaving any residue. This even applies to plastics with halogenated additives, which form aggressive decomposition products when they decompose (e.g. polyvinyl chloride/PVC => hydrochloric acid/HCl).
Thermal cleaning can be used to remove all organic contaminants from temperature-resistant materials. In addition to polymers and plastics, paints and varnishes, grease, food residues and much more can also be removed easily and perfectly.
The successful pyrolytic removal of (tire) rubber is highly depending on the quantity and composition of the respective material.
Components and tools that contain PTFE/Teflon seals cannot be thermally cleaned without first removing them.
Depending on the starting material and additives, the thermal decomposition of organic contaminants can lead to inorganic by-products or residues, which must be removed in a specific post-treatment process. The same applies to inorganic adhesions such as non-metallic corrosion inhibitors and ceramic residues.
SCHWING offers thermal cleaning systems in which the contaminants are decomposed by means of a thermal conversion process in a fluidized bed, separated from the parts to be cleaned and removed immediately. In this way, even the aggressive decomposition products are immediately separated from the parts to be cleaned and neutralized.
Depending on the cleaning system, the polymers or plastics are first melted off the parts to be cleaned during thermal cleaning and collected in a separate container below the process chamber for recycling. The plastic adhering to the parts to be cleaned or remaining in the tool is broken down in special (vacuum) pyrolysis systems or in a fluidized bed system. In cleaning systems with pyrolysis processes, the resulting carbon residues are converted into carbon dioxide with the targeted addition of oxygen.
All SCHWING cleaning systems have (optionally) an integrated or separate afterburning and/or scrubbing system to remove or bind the resulting reaction gases.
Parts to be cleaned
Thermal cleaning can be used to treat all parts made of heat-resistant materials that are generally resistant to temperatures above approx. 400°C. If the treatment temperature is lower, the cleaning time may be longer.
SCHWING offers specific cleaning systems designed for deep pore cleaning and short-term reuse of these special production tools. Depending on the contaminants, tool complexity, capillary geometry and part dimensions, vacuum pyrolysis systems (VACUCLEAN) are particularly suitable for this purpose.
The particularly gentle cleaning process in the electrically heated VACUCLEAN system consists of a melting-off, pyrolysis and oxidation phase specially adapted to the plastic used and the part geometry. Sophisticated sensor technology controls the fully automatic, eight to 30-hour cleaning process so that excess temperatures cannot occur at any time.
SCHWING's thermal cleaning systems enable the complete cleaning of even the most complex tools in just one step. The contaminants present in the tools are completely dissolved and decomposed.
For example, a spin pack can be cleaned even when assembled, depending on the type of polymer (PE, PET, PA, PP, Spandex) and tool geometry. The adhering polymer is removed in a single operation. Complete spin packs can be easily disassembled after cleaning. Inorganic residues are removed by means of a coordinated post-treatment such as ultrasound.
SCHWING offers the MAXICLEAN cleaning system for the thermal cleaning of large hot runner systems and components. The temperature controls the fully automatic cleaning process, among other things. Depending on the contamination and part geometry, thermal cleaning in a MAXICLEAN takes just four to eight hours. The electrically heated INNOVACLEAN fluidized bed system can clean small, non-overmolded hot runners in just one to a maximum of four hours - even with halogenated plastics.
Process
When cleaning extruder screws or simple film blowing heads manually, for example, the tools are treated abrasively with scrapers and brushes using a burner until the adhering plastic contaminants are removed. The disadvantages of this rather rough and time-consuming cleaning method, which is at most only suitable for very simple, smooth parts, are the possible damage to the tool surface and distortion due to excessive heat.
Thermal cleaning is currently the most environmentally friendly, fastest and most economical method of polymer removal. If thermal cleaning is carried out under vacuum or in a fluidized bed, particularly gentle parts cleaning is possible. SCHWING cleaning systems also work fully automatically.
Thermal cleaning is currently the most environmentally friendly, fastest and most economical way of removing polymers and plastics. Depending on the part to be cleaned, the contamination and the cleaning process, complete thermal cleaning can be completed in a comparatively short time.
- Thermal sensors attached directly to the parts to be cleaned prevent overheating and control the cleaning process fully automatically and digitally reproducibly.
- Perfectly cleaned production tools increase product quality, have a longer service life and help to minimize maintenance costs and downtimes
- Electrically heated cleaning systems and integrated exhaust air purification optimize the energy and environmental balance.
- Easy-to-understand user guidance via touchscreen enables flexible operator deployment and avoids operating errors.
The essential parameters for the cleaning time are the type and quantity of the adhering polymer and the geometry of the parts to be cleaned.
- Due to the excellent heat transfer of the INNOVACLEAN fluidized bed system, thermal cleaning only takes 1-4 hours.
- The pyrolytic removal of polymers or plastics in a MAXICLEAN takes 4-8 hours.
- Due to the particularly gentle polymer melt-off phase before the actual cleaning under vacuum conditions, the VACUCLEAN system requires at least 8 hours of cleaning time, depending on the grade of contamination and tool size or geometry. In individual cases, the cleaning time for film blowing heads weighing many tons can be up to 40 hours.
Thermal cleaning can sometimes be a highly complex process. The same parameters that determine optimum cleaning success are also required for the design of a thermal cleaning system. These include the type and geometry of the parts to be cleaned, their weight and number, the type and grade of contamination, the downtime available for cleaning, etc.
During the decomposition of polymers or plastics and their additives, irritant gases and other gaseous decomposition products can be produced in addition to the harmless carbon dioxide. These are neutralized in thermal afterburning plants or absorbed or separated in gas scrubber systems. All SCHWING systems comply with the relevant legal requirements.
After the actual thermal cleaning phase (pyrolysis, decomposition under vacuum, conversion in a fluidized bed), in which the adhering polymers or plastics are decomposed into carbon with the separation of gases, a specific oxidation phase follows in most SCHWING cleaning systems. In this phase, the remaining carbon is converted to carbon dioxide and discharged as a gas without leaving any residue.
Coordinated post-treatment processes may be required either due to specific contaminants that leave behind inorganic residues after thermal cleaning, or may be desired as a surface treatment for purely optical reasons.
Since the raw polymer of many plastics is provided with additional fillers such as color pigments, talcum, glass fiber or special additives, a coordinated post-treatment is recommended after the thermal cleaning of many tools and machine parts.
For service reasons, SCHWING blasts almost all cleaned parts with soft iron balls free of charge, making the cleaned parts look as good as new.
Components from the recycling industry, such as EREMA® laser filters, whose pores become clogged with aluminum particles during the recovery of polyethylene (PE) from film production (e.g. chip bags), must be post-treated in an approx. 45-minute ultrasonic bath in an alkaline solution with subsequent drying.
The same parameters that determine optimum cleaning success are also required for the design of a thermal cleaning system. These include the type and geometry of the parts to be cleaned, their weight and number, the type and grade of contamination, the downtime available for cleaning, etc..
The fully automatic system control of SCHWING cleaning systems, industrial furnaces and reactors records, processes and logs all parameters and data both for documentation in terms of quality management and for the reproducibility of the thermal and thermo-chemical processes.
Depending on the system design or model, this data can be read out via digital interfaces and used for preventive inspection (predictive maintenance) or remote service and support.
Quality control is based on the respective part to be cleaned. In addition to the PLC-supported cleaning protocols from the systems, SCHWING carries out fully automatic microscopic inspection systems for checking the capillaries of spinnerets, for example; the condition of filter systems can be determined using bubble test devices. In any case, a prior visual inspection by one of our cleaning specialists and their final recommendation for action based on the documented process parameters and results are essential.
The modern PLC controls of SCHWING cleaning systems naturally offer all the options for networking with the digital world in accordance with Industry 4.0.
- A VNC viewer can be used to access the visualization or user interface of the controller in the shared network.
- The machine's control system has an OPC UA server that can be used to query and save all process-relevant data.
- Finally, the machine's control system offers an FTP server (File Transfer Protocol) for easier evaluation of the process data. The internal data recording of the SCHWING cleaning systems can be loaded and evaluated from any workstation in the shared network.
Systems / Installations
Depending on the cleaning system, connections must be provided for the energy supply (electricity and/or gas) as well as for the cleaning process (compressed air, water).
The mechanical production of SCHWING cleaning systems complies with the Machinery Directive 2006/42/EC, the Low Voltage Directive 2014/35/EU and the EMC Directive 2014/30/EU (Electro-Magnetic Compatibility). Details are provided in the individual data sheets.
The emission limits for total carbon, CO, NOx and dust specified in the TA-Luft are not exceeded when operating a VACUCLEAN system. The basic compliance with the emission limit values (mass flow) of the German TA-Luft when operating a MAXICLEAN or INNOVACLEAN system depends on the type, composition and quantity of the organic contamination (polymer, paint, resins, etc.) as well as other factors. Further details are available on request.
For machine installation in Germany, for example, a total chamber volume of up to 1 cubic meter is only subject to notification; system volumes in excess of this require approval.
As a rule, every SCHWING cleaning system can be set up, loaded and unloaded, started and monitored by one operator. Comprehensive safety devices and a complete fail-safe design control the fully automatic cleaning process and do not require any additional monitoring or operation during this time.
Small parts such as injection nozzles, needle shut-off nozzles, non-return valves, screw tips or even smaller spinnerets, pelletizing discs, extruder screws and laser filter sets are cleaned particularly gently in the vacuum-assisted cleaning system VACUCLEAN COMPACT at temperatures up to 480 °C.
SCHWING's largest vacuum-assisted cleaning system is currently the VACUCLEAN 1713-XXL system, which can, for example, accommodate multilayer film blowing heads of up to 1.70 m in diameter and 12.5 t in weight and clean them in just one single operation. The design of pure pyrolysis systems varies flexibly depending on the application required. Thus, the MAXICLEAN pyrolysis system has already been built in multiple garage sizes.
The Cleaning systems of the VACUCLEAN brand use specific negative pressure to keep the temperature required to melt and decompose the respective polymer as low as possible. In this way, the metallic material structure of the parts and tools to be cleaned is particularly protected, which has a positive effect on the service life of particularly sensitive components such as spinnerets, nonwoven spinning beams or EREMA® laser filters.
Individual customer requirements such as special melting containers, dimensions outside the normal system dimensions, polymer-specific temperature curves and control programs can be developed and implemented on request. Further details are available on request.
The design of SCHWING cleaning systems is adapted to the specific needs of the customer. One example of this is the “VACUCLEAN 0917 Filter Bundle” cleaning system, which was specially developed for cleaning large candle filter bundles.
Plastic deposits on tool surfaces, residues of carbonized or degraded polymers and other contaminants caused by release agents or grease are removed using optimized post-treatment processes. Depending on the contaminants, the cleaned parts and components must undergo a coordinated post-treatment process. The most commonly used methods are:
- High-pressure water devices and ultrasonic baths to remove inorganic residues
- Compressed air devices for blowing off ThermClean sand (INNOVACLEAN fluidized bed cleaning system)
- Blasting systems (soft iron, plastic granulate, glass beads) for surface finishing or sealing of the cleaned metal parts
Services
SCHWING has been offering needs-oriented cleaning services for the plastics processing industry for almost 30 years. SCHWING now cleans more than 250,000 different workpieces every year according to the highest quality and environmental standards and reintegrates them into the customer's production process.
The parts and tools to be cleaned are provided by the customer ready for dispatch.
The shipping to/from SCHWING is either commissioned by the customer himself or can be taken over by the SCHWING transport service within a radius of approx. 350 km around our cleaning center in Neukirchen-Vluyn (47506).
Once the system has been installed, the SCHWING instructor first checks that the system has been set up correctly, including all of its supply and discharge lines and connections. The system parameters are then adjusted to the respective local conditions and the logging and documentation of all technical data is set up and checked. Finally, the system is tested for proper operation and a test cleaning is carried out using a SCHWING test batch and the cleaning results are evaluated.
During or after commissioning, up to three customer employees are familiarized with the operation of the system. These are usually the designated operator, an electrician and a mechanic from the customer.
After installing a SCHWING system and carrying out a test run with a specific SCHWING test batch, up to three employees are familiarized with the operation of the system. These employees are usually the operator, an electrician and a mechanic.
The introductory training covers the topics of safety instruction, system description, operating principles, editing the cleaning programs, operation of the cleaning system, acknowledging system messages and alarms as well as maintenance intervals.
In addition, special training courses are offered for system maintenance, troubleshooting and data evaluation.
SCHWING generally recommends servicing the cleaning systems after 2,000 operating hours or 1 year.
The telephone number and email address of the SCHWING troubleshooting hotline can be found on every type plate and in the operating instructions.
SCHWING customer service also offers 'Remote Expert Support' with the aid of modern augmented reality solutions.
If spare parts are required, SCHWING's After Sales Service will immediately ensure that they are correctly identified and shipped internationally.
Finally, multilingual service technicians are available for immediate, worldwide deployment.
The possibilities of SCHWING's worldwide 'Remote Expert Support' go far beyond pure “voice only” calls: In the event of a malfunction, the employees in 'After Sales & Service' can be reached in real time and, after an initial problem analysis, decide whether the diagnosis and rectification of a malfunction should be continued with the help of a professional augmented reality solution (Oculavis Share). This digital service enables SCHWING to significantly reduce downtimes and repair costs for customers, as the on-site deployment of a service technician would ideally be unnecessary.
SCHWING has been offering its customers in Germany and abroad comprehensive digital video support since fall 2020. This primarily relates to support in commissioning a new system, assistance with maintenance and repair work, and the provision of training and other services.
For example, commissioning a VACUCLEAN cleaning system with video support only takes around six to 12 hours and is spread over two days.
After a successful test run and commissioning of the new system, SCHWING offers additional operator training on a time or hourly basis.
All requirements from 'TA Luft' (Germany) and its European variants and supplements are met. Further details and specific information are available on request.
You want to learn more?
Please call +49 2845 930-115, send us an e-mail or contact one of our experts with any question you may have.
