Larger, slower mops reduce polishing fatigue
The normal method of polishing uses small polishing mops of around 250mm diameter running at fast speeds, but large diameter mops at lower speeds reduce fatigue.
The normal method of polishing employs a relatively small polishing mops of around 250mm diameter running at a relatively fast speed of 2800 rev/min. To learn to polish with this equipment takes months of training. The operator has to be extremely careful how he presents the part to the mop.
If the part is presented below the centre of the mop, it can easily be ripped out of the operator’s hands often resulting in personal injury.
Hand and wrist movements are frequent and vibrations are increased The contact area of the mop on the part is small, the fast speed creates a lot of heat.
It is not easy to master the art of polishing with such fast running, relatively hard mops.
After making the training investment the employer has a high risk of loosing the now skilled worker and on top of it faces the risk of costly compensation claims for injuries due to repetitive motion and vibration.
As the old generation of polishers die out the new generation is unwilling to spend their lives with such a dirty, injury prone and fatiguing job.
A polishing labour shortage has already developed.
It is yet another one of many reasons why manufacturing is moving East.
Ironically the reduction in manufacturing activity has helped to disguise these labour shortages to some extent but it will become more apparent in future.
There are basically two ways to address this problem.
Invest in automatic polishing equipment, ie CNC machines or robots or start using the more modern polishing system that has been in use on the Continent for over a decade.
There is, in the UK, considerable unwillingness to invest in state of the art automatic polishing equipment and unless this attitude changes the second option could be a stop gap measure.
The new manual polishing method was developed as robot polishing was introduced over 10 years ago.
Robots need to work with as few tool changes as possible.
New, 960mm diameter polishing mops were the answer and it did not take long before polishers saw their benefits for manual polishing.
With a 960mm diameter polishing mop the arc of contact is large.
At low 300 to 500 rev/min the operator can completely immerse the part in the buff without fear of having it ripped from his hand.
Parts stay cool and handling is more comfortable.
Polishing time is dramatically reduced and much less effort is required by the operator.
Finishes are more uniform because the cotton used in the make up of these large mops is loom state and not the rags used for small diameter stitched mops.
Mop life of two to four months is not uncommon.
An unskilled operator can be trained in days rather than months.
There is just one problem with the cool running, 960mm dia mops.
Conventional polishing compound have a relatively high melting point and when used on slow running, large mops will tend to leave black streaks.
However, new polishing compounds with lower melting points have already been developed.
They have the added benefit of being easier to remove in subsequent cleaning operations.
CNC polisher drastically cuts manual work
Polishing machine, used in aircraft parts, drastically reduces operator involvement by CNC operation of the grinding and polishing parameters, and the utilisation of load and force control.
Halifax, UK, based Crawford Swift has combined 130 years of machine tool experience, with the latest in CNC controls, to produce a new generation in glass grinding and polishing machines. The Crawford Swift Power Polish Machine drastically reduces operator involvement by CNC control of the grinding and polishing parameters, and the utilisation of load and force control. As a result the majority of the process becomes automatic, apart from loading and unloading, releasing the operator for other duties.
The machine built and commissioned for major French glass manufacturer.
St Gobain - Sully is used for the production of cabin and cockpit windows for the Airbus range of aircraft, and Euro fighter cockpit canopies.
A second order has also been received from Roshibus - a major Russian glass manufacturer and supplier of organic glass used on the MIG 29 aircraft.
The static and dynamic rigidity of the ‘Power Polish’ and CNC control provides the ability to grind and polish to much tighter tolerances than was previously possible.
The CNC control coupled with Crawford Swift’s unique design delivers load, force and position control via a touch screen PC The PC front end or manual pendant control provides ease of use for the operator and control of all the process variables and gives systems feed back with data storage and retrieval, allowing tractability of every individual component ensuring the highest possible quality.
The technology behind Crawford Swift’s new machine features a massive 4000mm diameter cast Iron, epoxy faced vacuum table and precision polishing spindle carrying quick change 1000mm diameter grinding or polishing discs, with through spindle coolant.
The spindle is mounted on a heavy duty oscillating overarm that traverses over the table.
In addition, the table and spindle counter rotate to provide a precisely controlled grinding and polishing action.
Carl Griffiths, of Crawford Swift said of the French order: ‘We are absolutely delighted that the ‘Power Polish’ is being used by our international customers’.
‘The feedback we have received, is that the machine is exceeding all expectations, and we look forward to going from strength to strength in this area.’
Diamond powder has high abrasion
Special regimes of synthesis provide diamond powder with high abrasive abilities in cutting and polishing applications for processing synthetic corundum (sapphire), quartz, composites and ceramics.
Our company has got a good experience of manufacturing synthetic diamond products, which are widely used in processing synthetic corundum (sapphire), quartz, composites and ceramics. Special regimes of synthesis allow us to make diamond powder with high abrasive abilities in cutting and polishing applications of the mentioned above materials. For wire cutting equipment we offer our ASN 15 in the following micron sizes: 30/15, 20/10, 20/14, 14/10, 12/8.
This product differs from the powders offered by other manufacturers in Russia.
The most outstanding features of our diamond powder are: the increased portion of monocrystals (up to 60%), shape coefficient 1.3 (actual sizes), portion of the main fraction up to 85 %.
Such features allow to increase the abrasive ability of the diamond powder up to 30-40% comparing to the other similar products currently available on the market.
The increased abrasive ability of this diamond does not cause any essential increase in the surface roughness after processing.
The choice of the powder size (fraction) depends on the type of the equipment utilized for wire cutting.
Also we recommend using our synthetic diamond powders, compounds and slurries for lapping and final stages of polishing operations.
The most widely asked materials for these operations are the following micron sizes: 8/4, 4/2 and 1/0.
The step-by-step surface polishing methods are also highly recommended.
The choice of the lap material as well as of the compound or slurry base depends on the types of the lap and equipment used engaged in polishing operations.
Pneumatic marking machine is portable
The PEQD-030 portable pneumatic marking machine is widely used on large-sized work-pieces or pipelines.
The PEQD-030 portable pneumatic marking machine is widely used on large-sized work-pieces or pipelines.
It has a marking scope from 130mm*15mm, 50mm*50mm, 150mm*100mm.
Rocker-suspended devices and electromagnetism- absorbed devices are available.
Pneumatic marking machine is computer controlled
The PEQD-100 pneumatic marking machine is widely applied in automobiles, motor accessories, mechanism, steel, petroleum, spaceflight and electronic devices.
The PEQD-100 pneumatic marking machine is widely applied in automobiles, motor accessories, mechanism, steel, petroleum, spaceflight and electronic devices. It can mark on accessories and labels of steel, metal, plastic as well as non-metallic material. The marking-needle vibrates and impacts in high frequency under compressed air.
The marking-needle will mark characters and graphs clearly on the materials.
The machine adopts the widely used ‘up-down columniation’ structure with extensive adaptability.
PEQD-100 Pneumatic Marking Machine is controlled by computer with software WINDOWS operation system.
Its powerful abilities enable characters and graphs to be easily made.
The marking-needle is made from hard-alloy.
PEQD-100 Pneumatic Marking Machine can mark date and series numbers to materials automatically.
Various marking-formats are available.
Lasers and marking supported by manufacturer
Wuhan Jiaxin Laser, a high-tech stock-share enterprise, specializing in exploitation, production and sales of laser machinery, is committed in providing excellent laser and marking support to users.
Wuhan Jiaxin Laser, a high-tech stock-share enterprise, specialising in exploitation, production and sales of laser machinery, is committed in providing excellent laser and marking support to users. Jiaxin laser products has an outstanding reputation from users in different areas and fields and provides an extensive series of products, including laser marking machines, laser engraving machines, pneumatic marking machines, brand imprinting machines. With reliable quality and reasonable prices, Jiaxin laser products have been exported to a number of countries such as Germany, Korea, Indonesia, Iran, Pakistan, Melanesia.
Jiaxin Laser accomplishes the whole process from software-exploitation, hardware-design, system-detecting to technical-supporting.
Robots abrasively finish, polish femoral knees
Robotic systems for abrasive belt grinding, buffing and polishing of cast components have also been successfully applied to femoral knee implants as well as turbine blades.
Messrs Intec of Italy have more than 20 years experience of designing robot cells for some of the most difficult parts, i e, surgical implants and turbine blades. Over the last five years IIntec have sold more than half a dozen robot installations for finishing surgical implants and turbine blades to US based manufacturers. This proves that Intec technology is not just the equal of US robot cell manufacturers but in many cases ahead of it.
The following report gives details of an installation for finishing artificial knee joints with a specially adapted robot cell.
The femoral knee finishing process consists of three separate operations: 1 - Gate grinding to net shape.
2 - Abrasive belt grinding.
3 - Polishing.
* Gate grinding - the gates from the casting process are normally located in the centre of the condyle where the arrow labels the ‘distal’.
The gates can be removed with abrasive belts grit 80.
The condyles and the patella track areas can then be ground with abrasive belts grit 150.
This process takes approximately 2 minutes.
Some Companies do not employ abrasive belts to carry out these grinding operations but either mill or use a grinding machine.
After milling robot cells with abrasive belts are used to linish the parts.
* abrasive belt grinding - the belt grinding operation takes approximately 3.5 minutes, with the exception of the inter condylar gap.
This gap is normally milled, but if it has to be abrasive belt ground the total operation of finishing the knee will take 5 to 6 minutes.
Finishing the inter condylar gap with an abrasive belts is possible but because of the long time taken we recommend this operation to be carried out by milling.
If we use four abrasive belt grinding units and do not finish the inter condylar gap the following finishing sequence is typical: * Abrasive belt grinding unit No 1 - finishes the condyles, condyle tips, lateral and distal sides, the patella track and the patella tip.
with abrasive belts grade X 65.
* Abrasive belt grinding unit No 2 - finishes the condyles, condyle tips, lateral and distal sides, the patella track and the patella tip with abrasive belts grade 45.
* Abrasive belt grinding unit No 3 - finishes the condyles, condyle tips, lateral and distal sides, the patella track and the patella tip with abrasive belts grade X 22.
* Abrasive belt grinding unit No 4 - finishes the condyles, condyle tips, lateral and distal sides, the patella track and the patella tip with abrasive belts grade X5.
* Polishing - after the abrasive belt sequence all parts of the knee are buffed in two stages: No 1 with sisal buffs and cut and colour polishing compo.
No 2 with cotton buffs and colouring polishing compo.
The cycle time for the two buffing operations varies between 3,5 and 5 minutes.
The above finishing sequence is used by one of our customers.
It is typical but we can also design other sequences to satisfy individual requirements.
* JIGS - femoral knees usually have pins, threaded holes or are of a box design.
Grippers are made to suit either of these designs.
In some cases it may be necessary to use two grippers so that all parts of the knee can be finished.
This involves gripping the knee in one position and one gripper and then gripping it in another position with another gripper.
* Three robot cells to finish femoral knees - depending on quantities and finishing specification up to three robot cells are needed to complete the femoral knee finishing process: * No 1 robot cell for gate grinding.
* No 2 robot cell for linishing parts all over.
* No 3 robot cell for cut and colour buffing with sisal buffs, followed by mirror polishing with cotton buffs.
If quantities are small and do not allow a three robot cell operation it is possible to concentrate all operations into either a two robot cell or even a one robot cell operation.
Obviously output will be considerably lower.
* Off-line programming - we can provide customised off-line programming with software options based on the state-of-the- art ABB off-line programming platform ROBOTSTUDIO.
The data input allows the user to use data formats such as CAD model, 3 scanner, a standard workpiece with a portable CMM and CNC path.
Automatic path planning aids optimised tool selection and work-cell design Auto path generation takes into account the experience of the operator A customised calibration method enables us to compensate for the error between the model and a real workpiece.
Simulation by the ABB Virtual Controller technology allows users to see the process and to obtain accurate process time estimation.
Robot linishing and polishing operations for surgical implants save considerable amounts of money.
A properly designed and configured robot cell can do the work of a dozen highly skilled manual operators.
Six axis robots can finish to tolerances below 0.o4 mm and surface finishes below 1.4 micron Ra.
An added bonus is greater consistency and the elimination of vibration induced illnesses and repetitive strain injuries.
Re-assess manual polishing mops
With fewer operators willing to undertake traditional repetitive polishing, to avoid the work going to cheaper labour areas, a supplier suggests a bigger mops for easier working, better results.
The normal method of polishing employs a relatively small polishing mops of around 250 mm diameter running at a relatively fast speed of 2800 rev/min. To learn to polish with this equipment takes months of training. The operator has to be extremely careful how he presents the part to the mop.
If the part is presented below the centre of the mop, it can easily be ripped out of the operator’s hands often resulting in personal injury.
Hand and wrist movements are frequent and vibrations are increased The contact area of the mop on the part is small, the fast speed creates a lot of heat.
It is not easy to master the art of polishing with such fast running, relatively hard mops.
After making the training investment the employer has a high risk of loosing the now skilled worker and on top of it faces the risk of costly compensation claims for injuries due to repetitive motion and vibration.
As the old generation of polishers die out the new generation is unwilling to spend their lives with such a dirty, injury prone and fatiguing job.
A polishing labour shortage has already developed.
It is yet another one of many reasons why manufacturing is moving East.
Ironically the reduction in manufacturing activity has helped to disguise these labour shortages to some extent but it will become more apparent in future.
There are basically two ways to address this problem.
Invest in automatic polishing equipment, i e, CNC machines or robots or start using the more modern polishing system that has been in use on continental Europe for over a decade.
There is, in the UK, considerable unwillingness to invest in state of the art automatic polishing equipment and unless this attitude changes the second option could be a stop gap measure.
The new manual polishing method was developed as robot polishing was introduced over 10 years ago.
Robots need to work with as few tool changes as possible.
New, 960mm diameter polishing mops were the answer and it did not take long before polishers saw their benefits for manual polishing.
With a 960mm diameter polishing mop the arc of contact is large.
At low 300 to 500 rev/min the operator can completely immerse the part in the buff without fear of having it ripped from his hand.
Parts stay cool and handling is more comfortable.
Polishing time is dramatically reduced and much less effort is required by the operator.
Finishes are more uniform because the cotton used in the make up of these large mops is loom state and not the rags used for small diameter stitched mops.
Mop life of 2 to 4 months is not uncommon.
An unskilled operator can be trained in days rather than months.
There is just one problem with the cool running, 960mm dia mops.
Conventional polishing compound have a relatively high melting point and when used on slow running, large mops will tend to leave black streaks.
However, new polishing compounds with lower melting points have already been developed.
They have the added benefit of being easier to remove in subsequent cleaning operations.
Wet abrasive band grinding applied to car trim
Messrs Cimotec, the leading German manufacturer of robot cells for mechanical finishing have developed a wet abrasive belt grinding process, which considerably reduces material costs and improves consistency and quality. The new process gives Western european manufacturers of CAE trim a chance to stay competitive. The car industry has rediscovered the shiny decorative strip as a way of enhancing the visual appeal of new models.
Even small cars are being fitted with one or more decorative strips of aluminium or stainless steel.
With middle and top of the range cars this trend has become even more evident.
A few years ago shiny decorative strips gave way to the cheaper plastic variety, which no doubt also fitted in with the spirit of the age.
As a result of these measures, manufacturing production capacity for high value polished decorative strips was reduced and demand fell.
Nowadays aluminium decorative strip is in demand once more, and ever bolder designs require new manufacturing techniques and more capacity.
Because of the incalculable element associated with the manufacturing of this high value product, especially where anodizing quality is concerned, outsourcing to countries with lower labour costs is not always successful.
It is necessary, therefore to build up and extend manufacturing capacity at home, even if only on the grounds of the shorter transport routes to the customer and the on-the-spot know-how in the manufacturing of these products.
As a rule a decorative strip consists of a pressed aluminium profile which is bent and mechanically processed.
With the vast majority of strips, a polishing process follows, while in the case of some strips with very pronounced bends, an additional abrasive belt polishing process is necessary to prepare the surface for successful polishing.
This polishing of high-value aluminium profiles is often a tricky process.
The aluminium alloys used for decorative strips are very soft and, after a certain time, the spaces between the abrasive grains on the polishing belts become filled with aluminium deposits.
This effect does not appear as soon with coarse abrasive belts as with finer belts, where the belt is often unusable after only a few parts have been linished.
The life of the abrasive belts is severely reduced while the costs and the problems rise rapidly.
The polishing materials industry has reacted to these problems and has developed a variety of strategies to prevent this effect.
Lubricants, compos and chemical sprays are applied before and during use on the abrasive belts and are intended to prevent clogging of the spaces between the grains.
Some manufacturers of abrasive belts have developed belts with a special coating which is also intended to prevent clogging.
These measures can lead to a significant increase in the life of belts, but the use of this process on robots or CNC controlled machines is not completely satisfactory.
Some years ago, in conjunction with a large polishing company that specialised in aluminium parts for the automotive industry, the old idea of wet polishing was taken up again and implemented in a robot-controlled wet polishing unit.
The idea is simple: water is used to rinse the spaces between the grains of belt.
Water can be applied without any problems in the right amounts and water pressures and volumes can be varied.
The aluminium rubbed off on to the belt is transported by the water into a filter where it is pre-cleaned first in sedimentation tanks.
It is then cleaned to the point where it can be used again.
Naturally, in wet grinding side-effects occur.
These are important to solve: the parts must be dried before being further processed.
The demands placed on work piece pallets and work piece holders are quite different from those during dry polishing.
The cleaning effect is so marked in the case of coarse 80 or 120 grain sanding belts that considerable belt life has been obtained.
Where finer polishing belts are concerned, with grain from 240 to 280, the volume of water used needs to be applied with great precision, otherwise a reduction of the removal action through aquaplaning will result.
Another very welcome side-effect of wet polishing is the cooling of the work pieces by the water.
When aluminium is polished dry, the parts can become very hot depending on the grain used, which can lead to problems later in the anodising bath.
The experience obtained so far, in three-shift operation, has been very positive.
With a few refinements to the wet polishing process and the choice of the correct belts, the process can be regarded as a considerable improvement on current practice for polishing aluminium work pieces.
The increased demand for these high-value work pieces means that robotic wet polishing has a long future ahead of it.
(Note ‘linishing’ is a registered trade mark of a US company - Ed).
Robots replace manpower to buff, polish guitars
World famous New York guitar maker has opted for sanding and buffing robots to solve problems associated with employee turnover, lost man hours and long training cycles.
When C F Martin opened his modest guitar making shop on Hudson St in lower Manhattan in 1833 he could not have conceived of today’s 190,000ft2 facility and 600 employees to continue the tradition of fine craftsmanship and solid business planning that has been the Trademark of C F Martin and Co for over a century and a half. The key to the Company’s longevity lies in their emphasis on quality and a dedication to the health of their employees. Equally important has been the ability of management to recognise and implement positive changes to the business model.
This is no more evident than in C F Martin and Co’s recent adoption of a robotic buffing system designed by Intec in Italy.
Like many manufacturers involved in high volume, high quality buffing, Martin had begun to experience problems with employee turnover, lost man hours and long training cycles.
It can take anywhere from six months to a year to properly train an operator in hand held buffing.
Once trained, the work itself can be tedious and the employee is vulnerable to ailments related to repetitive motion.
At Martin it was becoming more and more difficult to hang on to experienced polishers.
Even with the above factors the idea of robotic buffing was, at first, not an easy sell.
Over the course of a century and a half Martin had become widely regarded as the makers of the most finely crafted guitars in the world.
With quality of product and employee satisfaction ranking above raw productivity Intec needed to prove that their system was not simply about volume.
In order to do this Intec first introduced Martin to manual pedestal type buffing lathes.
Pleased with the results and with the service provided, Martin’s plant manager began testing the robotic cell.
Martin’s polishers were first observed and video taped by Intec’s programmers Then while developing the robot process program there was an even flow of communication between the two companies, ‘Intec was open to our input throughout the whole programming process,’ and worked with Martin over an 18 month period to develop an acceptable process in their robotic test lab.
After placing the order Intec’s robotic cell went through a rigorous testing period before it went on-line in 2004.
Since then the robotic cell has buffed over 20,000 guitars.
‘The cell produces very consistent repeatable quality which enabled us to reduce our manual polishing time of full gloss bodies by 50% and totally eliminated any manual polishing of our gloss top bodies,’ stated Martin’s plant manager.
Other benefits to the process abound.
Because of the size of the buffing wheels they are able to operate at a cooler temperature, reducing the chance of damage of the product being buffed and extending the life of the wheel.
Intec’s ‘Auto-Sense Buffing System’ also contributes to the economy and quality of the process.
The robot, part magazine and two buffing units are mounted on a heavy-duty welded steel double walled common base.
All the electrical and pneumatic connections run inside the common base eliminating any exposed wires and air lines.
The ‘Auto Sense’ electronic system for controlling buff pressure, utilizes a closed loop feed back system.
Up to five different pressures can be programmed and recalled at any point in the robot program.
This allows the buffing units to maintain a constant pressure while following the contour of the guitar.
In addition the system automatically increases the wheel speed to compensate for wheel wear, automatically maintaining a constant surface feet per minute.
The ‘Auto Sense’ system eliminates the requirement for program maintenance since it will compensate for the slightest part-to- part variation.
There are no second quality Martins, the slightest flaw can mean that the guitar must go back through the production line, or, that it must be rejected completely.
This has made consistency on the production line extremely important.
With the precision of its movement, and its adaptability through an extremely accessible interface that has ethernet capabilities, Intec’s robotic cell has excelled at creating a consistent product.
For the employees of C F Martin and Co there have been benefits as well.
Automation allowed some of our workforce to be re-assigned to areas where there were labour shortages.
A further benefit to automation is that there are now fewer lost man-hours.
Two former polishers have been trained as programmers, a part of the Intec service package.
The overall quality of the workplace has improved because the robotic cell is fully enclosed and ventilated, eliminating exposure to the dust generated in the buffing process.
The relationship between Intec and C F Martin and Co has continued beyond the development of the robotic cell.
Intec serves as a one-stop shop for contact wheels, buffs and polishes.
Because of their understanding of the entire buffing and polishing process Intec’s team have been able to continue to enhance both the method and materials for C F Martin and Co With the success of the automated polishing system the two companies are looking forward to more projects together.
The futuristic robotic cell is now prominently featured on the Martin factory tour and will be seen by approximately 16,000 people this year.
It is a testament to two companies grounded in quality and tradition, but with their eyes on the future.