Laser beam machining removes thorn for cactus

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-- laser is OK on purify cacti spinal, also can use at handling the appearance of other food, and do not produce loss. Graph 1, pome cacti in recent years, people uses laser to undertake material is machined, developed a lot of interesting application. Below a lot of circumstances, industrial group used laser to have cut, number, solder, clean and other application. However, in food industry, laser is used to potato of mark food, cut and cheese, and clean earthnut; Besides, laser processes trade in food and do not have too big as. Recently, people developed a new laser application, in order to solve a critical problem -- remove thorn for cactus. Pome cacti basically originates in Mexico, the history of the product is ages ago, its production and sale pervade a lot of countries. This plant nutrition is rich, healthful, and have officinal value. Go up in celadon, elliptic leaf bine (if pursue 1) distributinging move a lot of sidewall aperture, this aperture place is being enclothed be as long as the thorn of 3 Cm, there still is hair of a few agnails on the side of thorn. The fructification that they grow pleasant of a red, flavour -- pome, there also are a lot of thorns on pome. This product removes thorn with respect to need before edible, this process is moved by operation personnel hand normally or of mechanical use bit to remove thorn for foliaceous bine surface. This process caused the damage of the product, the bulk of attaint is amounted to 30% , storage life shortens, those who affected the product after removing thorn deposit and sell. Mexican CICATA-IPN company and Havana university joint development technology of a laser, this technology can remove thorn for pome cacti, the process that it is an ultra smooth ablation will remove thorn. Use this technology to won't destroy a product except thorn, reduced a loss, improved storage life. Graph 2, laser pursues except the sketch map laser beam machining that pricks a process 2 it is the sketch map that laser eliminates thorn chance. Cactus is placed to be on conveyer belt by linear ground, transmit the area that scans to laser. If plan institute is shown, use two Nd:YAG laser undertakes machining, can be opposite at the same time so the two sides of cactus undertakes machining. Beam of light is conveyed through the illuminator of translation cactus surface, such, laser is in as perpendicular as deferent direction direction, undertake scanning to product surface. Realizing a when automation goes pricking fundamental condition is to have the technology that can explore thorn in real time -- the existence that can explore thorn already, also can explore thorn already by the circumstance of purify. To achieve this goal, the locomotive mode of the machine beforehand set ordinal; In the begining, laser moves in the mode with inferior energy (make an appointment with 300 MJ) the existence that pricks in order to explore. Till this machine is maintaining exploration mode to explore thorn till laser; Explore the existence of thorn when laser, because intense light is absorbed,generated a typical acoustical signal. After this signal arises, sound detector issues a statement, so that will prick complete purify,demonstrative system raises energy. Then, big energy pulse (make an appointment with 1 J) be used at treatment, disappear till thorn till, subsequently acoustical signal also drops. Detector informs a system to restore to explore mode. Whole treatment is finished in the process that conveyer belt carries cactus. Graph 3, sound signal intensity and pulse the relation of several pursues 3 show, the pulse that sound believes mark strength to go up to thorn as application the change that number increases and produces. Advanced in the process that a few pulse machine, the intensity of acoustical signal rises quickly, reach maximum continuously; Should prick subsequently by purify hind, this numerical value drops constant. Before two pulse make the root ministry of thorn blackens. In this phase, acoustical signal is very weak still, because this vogue is had no any material ablation. Subsequently, combustion process makes sidewall aperture blackens, raised absorptivity, bring about ablating rate to increase, acoustical signal increases. Then, as absorb material to decrease, acoustical signal also drops. The fall of acoustical signal comes continuously absorb an end, finally, acoustical signal and plasma absorb a process to disappear. The advantage pursues 4 gave out to prick a process typically. Irradiation area has or a few thorn (there are 3 in graph 4a) , of thorn all round it is agnail wool (namely the Xiaomao all round bigger thorn is pricked) . From the graph 4b can see, after 3 pulse, the place remains to prick only with a few small burr. Inside a few area, short-haired pelt is pricked already by eliminate. Finally, from the graph 4c can see, after passing 6 pulse irradiation, whole area does not have big thorn, short-haired pelt is pricked also by take out, the area that leave is exceedingly clean, submit small hole form. Graph 4, go pricking a process: (A) before irradiation, (B) after the laser beam machining that passes 3 pulse, (C) thorn and agnail wool are after 6 pulse by complete purify. There is 40-80 about on the foliaceous bine of cactus thorn, because this afore-mentioned process need is on every thorn,repeat undertake. Use this technology, if every prick the pulse of a need to be less than 10, so of every leaf bine go pricking a process to need 600 pulse on average. 1J of every pulse energy, repeat system of laser of frequency 100 HZ, every 6 seconds can finish bine of a leaf go pricking a process. As a whole, of laser go pricking a process to machine a respect to have tremendous latent capacity in food. Current, according to cactus breed different, productivity is amounted to about horary a few kilograms, the power loss of such laser 100W is with respect to inadequacy. Smooth sound is explored make the real time that divides thorn is explored become a possibility, this assured the automation of whole treatment, also assured to machine quality. And, author already explain the patent that wins this new technology, this technology will be used at the treatment of food surface. The similar treatment result that uses this technology place to obtain already got test and verify on pome. Article author L.

Ponce (lponce@ipn.

Mx) , M.

Arronte, e.

De Posada and T.

Flores comes from Mexican CICATA-IPN company; B.

Lambert and J.

Cabrera comes from Cuba IMRE-Havana university. CNC Milling