Ever wondered why the head of a sewing machine is on the left side when most people use their right hand to work… Veteran technician and Senior Advisor, PFAFF, Helmut Jung speculates that it must have been conceived such because in the early days the machines were being operated on a treadle and every once in a while they wanted to reach for the balance wheel or the hand wheel to move the needle by hand and to place it in the right position, and since most people work with their right hand the machine supports the idea of the right hander… an interesting thought.
In an exclusive interaction with Team StitchWorld, Jung contemplates on some of the basic as well as the futuristic advancements of the industry adding “PFAFF was the first to build a dry head machine, besides developing the first 6000 RPM zig-zag stitching machine, the under bed thread trimmer (UBT) and the first chainstitch machine with a reverse facility.”
The main and the lower shaft driven by a belt system rather than using bevel gears
Some 50 years ago, most machines were driven by bevel gears including PFAFF’s, to connect main shaft and lower shafts. More work was involved to place the gears inside the machine; it was costlier and not as efficient and could not withstand the same speed, torque and force. Machines which involve movement in X-Y direction don’t use bevel gears anymore. Then came the time when ball bearings were used and now, we have the cleated belts which are a much superior option. They are made from synthetic fibres with steel cords inside and can withstand high speeds, torque and any force that the belt is subjected to.
[bleft]As long as we have humans on this planet who demand for garments and shoes, the future of this industry is very bright. As told by Mr. Bata from Czechoslovakia, he sent out two marketing people to Africa many years ago. One came back and said, “There is no market for us as people in Africa don’t wear shoes” and the other one said, “Lets make a market for ourselves as people there don’t wear shoes”. As long as people have individual tastes and fashion we’ll have business to do. [/bleft]
Seal the oil bed or the bearings
First, all the shafts especially the main and lower ones were running in bushings, so we replaced the bushing with lifetime sealed ball bearings because the bushings were one of the biggest drawbacks of this machine with an oil pump and an oil sump.
The biggest drawback with an oil sump and pump is of pressurized lubrication taken from below the bed plate, up the machine arm into the needle bar area. After running the machine for a while, it invariably develops some leaks and oil starts tripping out from the needle bar and cannot be taken back to the oil sump.
To overcome the drawback the gear box was kept below the bed plate containing all the drive mechanisms for feeding systems and it was completely concealed; however it was lubricated with foam padding and oil. Since it was completely concealed, nothing could come out.
As another first, we had developed the needle bar with a special synthetic coating with whose help we could do away with the lubrication of the needle bar.
Considering the low price points for machines but still giving all basic functions, we have forced lubrication with an oil pump because it is the cheapest solution.
[bleft]Electronics make it possible to reduce energy consumption such as: machines running for 8 hrs in a day using mechanical motors consume energy the entire time while those run on the electronic counterparts consumes energy only during the needle time which is approx. 20%.[/bleft]
Dry head machines
PFAFF was the first to build dry head machine almost 50 years ago with the technology being borrowed from the car industry. Like the older cars, it also required very frequent greasing and lubrication after every 1500 km. They used lifetime sealed ball bearings which never require any service. We also adopted the same technology in our 460 series around 50 years ago and this was in fact the first dry head and semi dry head in the world.
Completely dry machine are not very favoured by me. The dry head hook has life expectancy that is one-third as compared to a normal sewing hook, and speed wise also one is limited to 4000 stitches per minute. In the shoe and leather industry, oil is required for some purpose other than just lubricating the hook, you need to wash out the small particles which are being punctured out by needle entering the material thus resulting in a lot of abrasive particles in the hook reducing its life cycle enormously. Other manufacturers in Asia may claim of having invented dry heads but being in the trade for more than 50 years, I am still not satisfied with their claims. Dry headed machines are minimum lubricated machines that will be seen more and more in the future.
[bleft]We plan to increase the needle time by around 50% and eliminate some of the handling processes by using easier methods of preparation. Handling procedures can also be reduced by better work place layouts thus improving the efficiency.[/bleft]
Speed limitations in normal, semi dry and dry machines
The speed in the completely dry head where the hook race is coated with some synthetic material can only stand up to approx. 4000 RPM. Running at higher speed would lead to a premature wear and tear. You would lose the coating and therefore lose the lubrication or the lubricant effect. This does not mean that the dry machine is on its way out but I believe today the industry has settled for minimum lubricated machines.
No one can use the high speed machines; there are only a few operations such as side seaming of pants or surging of trouser panels where you can go flat out at high speeds. All other operations are done at a mean speed of around 3000-3500 RPM which is quite attainable in a dry head machine. It will improve the seam quality.
Why go for 5000 RPM when you need only 3000 RPM. It doesn’t make sense. The high speed machines also increase the chance of feed puckering. Because of the high speed, the feed dog comes up and hits the presser foot and the impact leads to reduction in the pressure of the foot. Due to this the top ply is not fed properly, while the bottom ply of the fabric which is in contact with the feed dog is fed normally leading to a differential feeding of plies, causing puckering. The machines running at a higher speed require higher pressure of 5 to 6 kilogram of weight for proper feeding. This results in an inferior quality of seam.
Maybe in a couple of years someone will come up with a machine in which you can reduce the pressure on the foot to such a level that there would be no more feed puckering at all. This is a real advantage and maybe we would see it in the next couple of years.
PFAFF is the only company which has come up with the speed responsive presser (SRP) foot machine. The presser foot with this technology adjusts its pressure in accordance with the speed of the machine. The technology is still the only solution to reduce feed pucker substantially.
The growing use of direct drive
The biggest advantage of a direct drive system is that it saves energy and also secondary costs. For example, it saves money at the factory where the machine is being assembled because the assembling processes have been simplified due to the use of direct drive. Secondly, before the machine is being installed, the technician or dealer has less work to do thus leading to savings of secondary costs. Earlier with the conventional type of motor, there was under table mounting and belt adjusting which needed to be done. Further, the size of the motor has also been reduced drastically and still being powerful and it is also beneficial to the operators because they get more leg room under the table, etc.
There is no real disadvantage of direct drive, except that it can breakdown if the power supply is not stable. If you have power surges or power failure, direct drive motors may experience some breakdowns despite having protective devices. But with a proper and stable power supply systems, there would be no problems.
Two different motors, one for the upper and other for the lower shaft
I don’t foresee a future in using two motors as all attempts so far have failed because of the cost factor since you need at least a computer to drive this machine. So, for a normal single needle what’s the point for the sake of the technology to have an expensive machine with a motor driven hook and a motor driven upper part? I know for a fact that Brother and an American company, have attempted this technology but all attempts have failed. Maybe in 10 years, when the computers become cheaper, two motor technologies may become viable but certainly not in the next few years.
Sewing machines are always built like a “C”. You have the main shaft connected to the lower main shaft to drive the needle bar, take up lever and the hook. So what do I save by employing this technology. There may be some minor advantages like if you want to change the timing of the hook you could possibly do it at the push of a button by advancing or retarding a few increments but how often one has to do that. It was a nice try but not everything is successful.
Standardization of the machines on a common platform… for easy replaceability with limitations
It has been the dream of all machine manufacturers to have one platform. If you look at our new series, the Powerline, you can identify a platform offering the same housing or chassis as in many different feed mechanisms and single or double needle machines, but again we have our own platform. We have gone one step further with few parts such as the feet or the feet components or the hook of our new powerline generation (2235, 2545, 2546, 2595, 2596) are compatible with Duerkopp or Juki because PFAFF can supply these wear and tear parts to the manufacturers or many a times the manufacturer may argue to keep his stock on spares down, buy his spares in the open market or does not have to rely on substandard copy parts. We have on purpose designed our machines so that the parts are interchangeable with Juki and Duerkopp that makes the acceptance of our machines much better in a factory.
Certainly a common platform is a good thing to have and is desirable but unfortunately, there are limitations to it. We are using the platform now on our small area bar tack machines, we use it on a post-bed machine for upholstery and for shoes and we also use it in our flat bed machine for upholstery, leather goods and so forth but we will not be using it on single needle.
There are certain technical difficulties in its implementation because by nature, the need of different machines is dissimilar… You cannot make a platform for button-hole machine out of a single needle lockstitch platform or you cannot have a light weight machine platform common to that of a heavy duty machine.
Similarly, you cannot have an overlock machine out of a lockstitch platform system. Within a family there can be a platform. You may try to have a common platform but it won’t be compatible across different machine families.
Ultra sonic welding to replace sewing
Absolutely not… it is the process of putting a garment together which is much more expensive. There are certain areas like functional wear and protective clothing which are chemical proof where welding will be employed, but to say welding may replace stitching is not possible because it is far too expensive and much slower. Isolated individual operations in bra and similar industry make sense but welding must always be seen as an addition to sewing. The only advantage is when it comes to extremely stretchable fabrics, the stretchability in sewn seams is normally limited by the seam, i.e. it will go as far as the seam allows it to go but with ultra sonic welding it will go as far as the fabric will allow it to go.
One of the first garments which was made seamless was a bra and they are already on their way out. The smaller sizes are okay but the larger sizes by the virtue of weight destroys the wearing comfort of the seamless bra because we follow the law of the centre of gravity. Ultra sonic must be seen as an addition to sewing and not as a replacement.
Machines with no needle movement and only clamp movement, why?
Earlier button sewing machines of PFAFF employed technology where needle used to have a throw laterally (like a zig zag machine). For a 2-hole button, clamp movement was not necessary. For a 4-hole button only the clamp used to move longitudinally. Japanese machines used to have no needle movement and only clamp movement.
There can be no doubt that a button sewer with a moving needle bar is always superior to the so-called fixed needle bar machine. The fixed needle bar machine is subject to more mechanical wear and tear (less weight on a shirt than on a coat or jacket) and yet in the shirt industry this type of machine was quite successful due to the light weight of the material being sewn and also because of price…Today the technology has undergone some drastic changes – the lock stitch button sewer with a X/Y control and a combination of fixed/moving needle bar has taken over.