Water jackets cleaning

One of the more difficult areas to clean in the cylinder heads and cylinder blocks of the automobile engines is the water jackets,Why?

1) The internal volumes of the water jackets are complex and very often with narrow passages. By one side the cylinder head designers wants to have a minimum water jacket volume in order that the engine can rise in temperature rapidly to have the optimum engine performance. By other side is important to refrigerate all the areas of the cylinder head , mainly around the combustion chambers , but the number of valves per cylinder create narrow passages inside the water jackets.

2) On the machining of the aluminium alloys the cutting speed are more and more elevate and create longs chips . The cycles times on the machines are more and more shorts and there is not too much time to break the chips.On the transfer lines it was easier to do than in the present CNC flexible lines.

3)As consequence of the cutting speeds and short cycle times the chips are very often pushed inside the water jackets by the final milling tools.

4) The consequence of long spring chips inside small pockets and narrow passages  is chips trapped inside the water jackets.

The cylinder head is more sensitive to this problem but some cylinder block too. Here joint you can see what you can find inside a cylinder head water jacket:

       There is a clear test : If we cut a supposed clean cylinder head in slices it will allows us to see if there are some chips trapped inside the water jacket. I’ll say that the majority of clean cylinder heads have chips inside.

Is dangerous for the engine run? Well, first you have to assembly your engine (cylinder head , cylinder block , camshafts, crankshaft..). During the automatic assemply this remaining chips can fall down of the parts and goes to the assembly machine or between the parts to be assembled blocking the operation and stopping the machine and the line.

Second if you assembly your engine with no problem but the chip remain inside , is possible than during the engine run with the vibrations and , temperature changes , the chips goes out of the water chamber and arrives to the water pump causing the failure of the water pump , heating the engine and stopping the car engine.

Another added problem is the remaining sand balls remaining inside the water jackets coming from the cast process:

 

 

 

Since many years this water jacket problem has been the major nightmare for the equipment suppliers and for the automotive industry .

The process to remove the remaining sand inside the water jackets  is called “desandind” and will be considered in a further post . today we will concentrate only in the chips removal :

Some suppliers were using a contact jet at 20/30 bars to flush inside the water jackets( ICOM, Hafroy). Or” injection flood” ( Dürr) injecting 10/15 bars jet against the waster jacket on immersion of the part . Or the “Aqua cannon”(Valiant) with a medium pressure short discharge inside the part pulsing the water inside. 

Or the High pressure ( 200 bars) target injection trough the part openings (Agullo).

Or a mixture of systems like Sugino .

In any case the problem is a difficult problem and needs test with real parts to achieve an acceptable process. Of course the automobile client is also an important part. If the cleanliness test to control the cleanliness of the cylinder head is a manual flushing of a solvent trough the part( and water jacket ) is probably than the flushing (normally at 1 to 3 bars) will not be able to remove the blocked chips inside the water jackets and the test can give a result of accepted clean part when it has trapped chips inside the water jackets.

Some cleanliness tests in the automobile have added operations to the cleanliness test procedure to verify these water jackets. One is the manual hammer percussion by the operator of the cylinder head in a certain position in order to detach the chips balls inside . I remember than years ago in an european engine manufacturer the company Hafroy supplied one transfer machine that had a pneumatic hammer in one of the Ferris wheel wash stations to reproduce the operator cleanliness test operation and try to remove this balls. I remember that the line operators call the machine the “Bell” ( a “dong” each 30 secs was not appreciated by the operators around the line).

Another system is the manual checking of the water jackets with a small  endoscope . This system is of course the more efficient but some times you can not reach all the internal areas. Only cutting the cylinder head you can really check it.

To reduce the chips and traps inside the water jackets is necessary a close work between the cylinder head designers ,cylinder head  machining engineers and the “cleaning” engineers to avoid narrow passages inside the water jackets design , to avoid big and spring chips during the machining, to have high coolant volume during the machining , or cover plates during machining . If you diminish the size of the chips , if you avoid the spring chips , if you avoid narrow passages and traps inside the water jacket , if you have more than one opening of the cylinder head water chambers you will have more opportunities to remove the inside trapped chips.

Maybe one of the Automobile manufacturers that pay more attention to the water jackets has been Fiat . In their wash process specification the request several water jacket wash operations in each of the washers of the cylinder head line. More water jacket wash operation you have with the part in different positions and injecting the water by different areas to create different flows inside the water jackets allows them to have more opportunities to remove the chips. Of course this redundant system is expensive and the present tendency in the Automotive industry is to reduce the number of washers in the lines.

In any case the miracles are impossible and if you really check inside your cylinder head water jackets(or cylinder block water jackets) you have to pay attention to the whole manufacturing process including the more effective wash processes to remove the trapped chips and to have a really clean part.

 

A good system is to collect and classify all the chips shape produced in the machining line , operation by operation .  

And then looking to the chip type remaining inside the W.J. you can identify in which machining operation the chip is produced and penetrates in the W.J. Working with the machining process engineers it comes very often the possibility to reduce the size of the chip or to eliminate the quantity remaining in the parts

 

The automobile cleanliness tests procedures are also an interesting point to be examined in a further post. They are the reason why some time one washing machines that is a good machine for an automotive manufacturer but fails in another manufacturer.

Cylinderhead Brush deburring(1)

Many components of the automobile engine are in aluminium .When the aluminium parts are machined it remain on the edges small parts of material that we call burrs.

These burrs have to be removed to avoid problems during the part assembly or for the good mechanical function of the part.

The action to remove these burrs is known as “deburring”. According with the areas where are located these burrs there are several ways to removed it in high production processes: by brush deburring , by abrasive blast , by high water jets, electrolytic, walnut shell, thermal deburring, paste deburring, vibratory bowl abrasive deburring…

The most used in the automotive  industrie for the cylinder heads are the brush deburring and the high pressure water deburring.

There are a lot of suppliers for the deburring equipments but to have a cost productive process the best solution is to include the deburring process on the wash process. Why? . Because the parts after machining or after deburing have to be washed as well and because the brush deburring with aluminum parts has to be made in wet conditions .

The brush deburring and the high pressure deburring have been the two technologies better integrated in the wash lines.

The first integrator of brush deburring in the wash lines was the company AGULLO in the late 70’s. The first machines were supplied to RENAULT in France for the deburring of aluminium cylinder heads at high production (300 p/h). The cylinder head combustion , cam and manifold faces were deburred with automatic brush deburring units located at the entrance of an in line lift and carry transfer washing machine.

The brush deburring units to increase their deburring efficiency have evolved to planetary brushes where several brushes rotated on their shaft at the same time that theirs shafts rotated around the main shaft. These planetary heads have been for many years a reference on the brush deburring having a combined action to remove the burrs of the edges.

In a cylinder head machining line there are normally three wash operations : Primary,intermediate and final . The deburring operations are incorporated generally on the intermediate and the final washers.

 In the  intermediate washer there is the brush deburring of the cylinder head camsahft face , and the complete wash of the cylinder head before the bearing cap assembly .

On the final washer the machine  incorporates the deburring of the remaining faces ( combustion , manifolds, and extremities faces) . According with the production rate and the number of faces to be debured  the final washers became big machines (till  13 mts. long) and the PLC softwares complex. For these reason it was a tendency in late 80’s to separate this last brush deburring operation of the final wash operation in two machines: one machine for deburring with brushes and one for high pressure final wash-deburr.

The cylinder heads had more and more areas to deburr and the final cylinder head deburring became a self transfer complete machine.

 

Late 80’s the high pressure water deburring was also applied in high production cylinder heads . The first high production machine in Europe was supplied by AGULLO in Ford UK with 600 HP power and four high pressure pumps.

The high pressure water deburring can deburr faces but also has the advantage to allow to deburr oil galleries intersections and in the final washers the high pressure wash become also a standard to allow high cleanliness levels . In consequence the high pressure deburr is used in the final washers as a complement of the final wash operation.Having then the high pressure pack on the final washer why not to use the HP water for a complete deburring of the cylinder head? 

Of course this could be an option but the operational cost of a high pressure deburring operation is 2 to 3 times more expensive that for the brush deburring . In consequence anything that can be effectively brush deburred is better to do it with brushes than with high pressure water.

In the present the aluminum cylinderheads or the aluminium cylinder block flat faces are preferably deburred with brushes keeping the high pressure water for the oil galleries intersections , or other small deburring operations (oil galleries , bearing cap intersections, oil feed…)

 For a new part project ( i.e. cylinderhead) is possible to identify areas where the burrs will be present after machining and that have to be removed. But you can not identify 100% of the areas .Some times due to machined areas intersections with cast areas the burrs are present but not  in an predefined position .For this reason is useful on the cylinder head final washers to have a high pressure water jet programable with CNC or robotic  and a reserve of several seconds on the cycle time to can solve these unexpected burrs .

The brush deburring for flat surfaces is the more cost efficient solution compared with the high pressure water , but the high pressure water can reach areas where the brushes can’t.

Now in the market there are several companies proposing the planetary brush deburring heads .

The recommended brushes are the cups with stainless steel wire , but for certain aluminium the abrasive wire is also wellcome.

In  next post we will explain how to manage the brush wire wear compensation.

Robot cells : wash / deburr

In the STUTTGART Parts2clean exhibition , a lot of WASHER manufacturers were claiming their ability to supply robot applications for the wash and deburr process.

The application of robots in the wash/deburr is not new. Late in the 1980’s AGULLO was one of the first companies in the world to look for the application of these technologies. In this time the robots were mainly hydraulics or pneumatics and the main robot suppliers were the Americans UNIMATION ( Polar-articulated) and PRABB( cartesian) .

 To look closely to this applications I remember that I visited these two companies in USA , and both were proclives to decline any warranty of the robot working in the wet and dirt conditions of a washing machine.

Why? : The conditions inside a wash chamber are very inconvenient for the robot : water splash, possible direct contact with high pressure jet( 150 to 800 bars), hot ambient ( 50 to 70ºC), high humidity air , vapours , condensations ,  solids dirt , mechanical chock due to the chips removed from the part that can crash against the robot arms as bullets…

For the part gripper at the end of the robot wrist the same problems that for the robot : water , humidity, condensations, temperature, mechanical bullets… and additionally : problems for the electric switches and wiring , and pneumatic hoses ,controlling the open/close positions of the gripper. 

So de-couraging was the result of these visit to USA that in the AGULLO company it was decided to design a specific robot to respond to the difficult conditions of the wash/deburr operations. The Market was requesting machines able to wash different parts, in the same machine, and at low production and the robot could help for that. The classic washing machines had then wash box fixtures with pin point jets adapted to each part to be washed . If the parts to be washed were different , then it was necessary to change the wash boxes of the machine at each time that the new part arrived to the machine.

For certain machines like crankshaft washers , or cylinder head washers , it was possible to create one fixture that was carrying he wash boxes and then the operator could change the complete package for each new part. With the cylinder block washers the wash fixture becomes heavy and requested a lot of time and hand labour to be changed. A robot (despite his high price) could simplify the work with only a wash robot program to be stetted for each part.  

The result in 1983 was the design of a Cartesian robot , five axis ,with all their mechanics and servos on the opposite end of the arms( patented) .The payload was 350Kg and a prototype for validation was build in the Barcelona Agullo factory. Some of the customers robot experienced people visited the robot and gave some feedback. The most important  was coming from a Mercedes robot engineer suggesting to switch from the hydraulic servos( American Moog) of the prototype to the electric drive system as it was the future for the robots at least in Europe. The robotic electronic command was also another concern . Too much electronic companies offered robotic commands in the shows but they didn’t have experience in the field. By other side the customers didn’t like to train their people to each robotic command of the suppliers .

Another concern was also to consider if instead to grip the part to be washed to the robot arm , if it would be faster and agile to move the jet with the gantry robot and leave the part static. Then instead to need a 300Kg payload to move a cylinder block to wash and his gripper , we would need only a 50 or 70 Kg payload for the high pressure applications. Finally the decision was to re-convert the design to a Cartesian gantry robot with electric drive and servos with CNC controls ( Siemens or Allan Bradley the more popular then in the field ) and to move the jet. Totally a four axis gantry robot CNC controlled , working against the part to be washed presented in a fixture , or an in line transfer or a rotary table transfer. The fixture could have a supplementary CNC axis giving a total of five axis , enough for the wash/deburr process.

With this gantry robot located in the roof of the machine , with folded bellows to close the gap on the roof , all the mechanical an electrics of the gantry were outside the machine well protected against any water splash , or condensations. No mechanics neither electrics were on the wet area of the machine but all was outside the machine in the roof for easy access.The CNC command was controlling the gantry robot and the machine itself.

This AGULLO gantry robot was build for more than 17 years , around 100 units , and a derivative of it is still supplied by Dürr Ecoclean on some Rotary transfer washers for cylinder blocks and cylinder heads applications. There is one of these gantry robot 14 years old that is still working in his washer.

Why I have explained all these past experiences?  Because the alternative to the gantry robot using the articulated robots in the machines was difficult years ago. The first that I know were used the Smart-COMAU(Fiat) for the Borg Warner USA compressor applications but with the articulated robot outside the machine , vertical, on the floor, and with a complete vertical circular bellow wall to protect the robot. This bellow last normally no more than one year in normal conditions but with accidents or bad manual movements it has to be replaced very often. The english manufacturer CERA was also trying to use the same robot layout but with ABB robot.

In France Renault developed also one small vertical Cartesian robot that was used by the french company Brochot on the machines supplied to Renault to clean / deburr gear boxes but with many problems on the belows and mechanics, because the complete robot was inside the machine.

Fanuc was also marketing his small articulated robots for small wash applications ( first in japan and later in USA), but with frequent disassembling for maintenance.

Then ABB pushed also his robots . They were applied in the high pressure jet cutting located in the roof of the water-jet cabinets , and this application inspired to certain washer manufacturers to use the articulated robots inside the washing machines. 

 

Manufacturers like STIC_Hafroy in France and ICOM in Italy , Eurowide in England used the ABB in the roof with a big textile wrap ( moving the water jet).

Today the articulated robot suppliers have improved their robots and now they start to propose a better water protection to the end wrist and to the robot body . (As is the case of ABB and in a second place Fanuc,may be we could also add Staubli if his last robot runs well). In consequence there are more and more manufacturers that they propose “robotic washers” using standard robots of the market.

A lot of robot  suppliers assure IP67 protection for the robot ,but maybe we have to remember that IP67 protection in the robot is not enough for a wash deburr application . You would have to go to the “electrics standards” and see what means “IP67″ . The first digit”6″ means solids protection :”power dirt protection” .The second digit (“7″) is a water protection but “7″ means protection to the water inmersion without pressure for 30 minutes¡¡ Inside a wash/deburr cell , there is high pressure water ¡¡

Some robot suppliers claim higher protection :”IP68″ , but again please note that the digit ”8″ means “harder conditions (to be defined by the supplier) of immersion than the IP67″ but still immersion , not protection to the high pressure jets.

What means all that ?, that the washer manufacturer who is proposing to a client a “robot cell” with an articulated robot of the market needs to add some additional engineering to his machine for additional protection of the robot . If not, the client is taking a big risk ordering a machine to this washer  manufacturer. 

But there is still a confusion using the term “robotic washer”. What is better to move the jet with the robot or the part against the wash/deburr jet?. We will see in a next post…

Part2clean Stutgart (4) Rotary transfer washers

Out of the already commented rotary transfer machines for small components , in the Parts2clean show I noted other manufacturers that they are active to wash or deburr bigger parts ( main powertrain components as cylinder block, cylinder head, crankshafts, gear box…).

Almost all the manufactures of these machines were German , and only few “foreign”. One of this foreign manufacturers was the Italian Tecnofirma. This company is an “old” company in the business. At the beginning mainly present in Italy . Years ago it started to wash cylinder block and cylinder heads Automobile components but the presence of AGULLO and ICOM in Italy stopped their development in the 1990’s . They were limited to crankshafts transfers or gear box components so long as AGULLO and ICOM had orders for the cylinder block and cylinder heads in line transfer washers for FIAT.

Tecnofirma developed rotary transfer washers for other components related to the motorcycles , tractors or gearbox components in Italy and also for the customer subsidiaries in Latinamerica or East Europe.. Now is improving his sales action in Germany and France , and they presented an interesting rotary transfer wash/deburr machine ( four stations) with an small ABB robot carrying a jet for the flex wash or blow-off.

 

 

 

 

The robot is applied directly inside of the wash chamber and has a jet on his wrist.

The High pressure pack and filter is installed in a separate module with the classic Hamelmann piston pump. The filtration is trough a safety cartridge filters and automatic paper filter

The machine has a robust look and the price announced seems interesting. Tecnofirma has a good experience in mechanical components customers. I hope that they can have a development in the next years if they achieve their export development.

Another of the “foreign” exhibitors was the Japanese SUGINO .This company has also a long history on the wash-deburr business. Their main market is the Japan companies and their transplants to other countries.

SUGINO has the best experience in high pressure applications in the wash and the deburr. Don’t forget that the Japanese automobile companies were the first ,worldwide ,to improve their cleanliness levels using high pressure water in their washers and after using also the high pressure for the deburring.This Market was advanced against the European or American markets.

SUGINOis the sole wash producer in the world, that I know ,that is also producing their high pressure pumps. In fact the division of high pressure pumps and his applications in all the industries is one of the hard points of Sugino. They have several patents and the advantage to produce themselves also the high pressure accessories ( 2ways valves, safety valves, HP jets, lances, distributors…).The use of the high pressure goes till to the jet cutting at 4.000 bars

Surprisingly despite their high experience and acknowledgement in the high pressure they have been not active in Europe. Their competitor KITO at least supplied Toyota in UK but Sugino has been out of this market. In USA they sold some machines 15 years ago in the gear box Ford factories but they din’t push too much the market and remain anecdotal.

Is really a pity because for me Sugino has experience , acknowledgement and inventive. Some tricky devices and original process invented by them ,and not yet discovered by the German suppliers( neither Americans), are fantastic and very efficient.

In the Parts2clean exhibition they presented the “Jet Clean Center”. Is a cell with CNC axis that allows to high pressure wash and high pressure deburr small components . These components can be manually load or robot load.

The must interesting thing of this machine is the Turret tool jet head. The turret has 6 possible different high pressure jets or lances that can be feeded individually trough a HP distributor. This machine is valid for small productions in a cell configuration and has been the first machine on this business to adapt the form of a High pressure cell , idea reproduced now for a lot of manufacturers.

 

SUGINO has also a family of rotary transfer machines for cylinder blocks and cylinder heads . The machine with two , three or four stations is integrated on in line or in cells productions . Recently they have supplied these machines for the new Mazda-Ford factory in China. They have a combination of the machine with a Cartesian 4 axis wash gantry robot located in the roof totally outside the machine as Durr Ecoclean Barcelona had.

The originality of their machine is that the load/unload of the parts can be made automatically without any further device .A vertical movement of the complete rotary table allows the part to be load/unload on a conveyor at the same time that the same vertical movement of the table allows to better wash and blow-off the parts in the other stations.

The application of the gantry robots instead of anthropomorphous robot in the high pressure wash-deburr applications is an interesting debate that I will write about in one further post after also a further robot cells post.

The weak point of these machines is that the indexing driving device with the vertical movement of the table is inside the machine , not easily accessible for maintenance. To do the same process the design of the Dürr Ecoclean Barcelona transfer rotary machine was much better solved with full accessibility to all the mechanics either rotary , lifting or gantry ( but more expensive of course).

In general the SUGINO wash-deburr processes , and high pressure devices are original,tricky and effective. The mechanical concept of the machine and their sizes are really designed for the Japanese Market . The design should be hardly modified to support the European rules and standards and by this reason is very difficult that some European client accept their machines standards. Is not their fault is a question of market demands. Something similar happened on the first machines supplied to Ford America.

But for markets like the Japanese or China, Korea..where the demand for big access for maintainability , and safety rules are not so stringent than in Europe , these machines are valid. But as the price is also important and these solutions are chipper, the client has to balance his decisions.

SUGINO has now a subsidiary in Chekia for his division of machine tools. It would be maybe a good opportunity for them to redesign their machines for the European Market demands.

OK ,that’s all for today. See you soon in my next post.

Wellcome

After 36 years of work in the washing , cleaning and deburring of mechanical parts for all the automotive Industry around the world ,I’m starting now a new complementary activity trough this Blog.

It has been a passion , an a very innovative world.

More than 1.000 washing problems , 1.000 special applications all around the world following the needs of better quality in the Automotive Industry .

From Spain to France at the beginning ,and after to UK, Italy, Germany, Russia, USA , Canada, Sweden, Brazil, China, Mexico …

Thousands of experiences and anecdotes helping the automotive engineers .

Now I’ll try to continue to help the new automotive engineers arriving to this strange world :

Why I have to wash the part ? ….How clean is clean ? ….Why the washers become  Machine tools? … Robotic washers?…Deburring?..

This Blog is in preparation. Hopping to meet you soon.

Juan Agullo

Cleanliness Management and Engineering

Barcelona