DE1927929B2 - Process for processing a workpiece surface - Google Patents

Description

odei synthetic long-chain polymers with a much higher viscosity than the linear chains essential to the working fluid and a molecular weight alone. It would be expected that the essential weight between 10 * and 7-10 «in an amount of higher viscosity of the working fluid with the 500 to 30,000 parts per million parts of water and dissolved long chain polymer, the flow throughput, if necessary 3. one for the dispersion of the load and the velocity of the liquid stream agreed long-chain polymers required too- greatly reduced or even brought to a standstill, set of alcohols with 1 to <i C atoms and since the viscosity normally increases optionally 4. finely divided solids - do not use pressure in a fluid significantly will be. The invention makes the cohesion smaller.

and energy density of the Hochgeschwindigkeils fluid io In Figs. 1 to 5 em Hochgeschwiadig-

fluid jet increased and the tendency to disperse fluid jet demonstrated a conventional one

of the jet leaving the can is reduced. Equal device for generating jets of liquid

at a certain working pressure is shown in Fig. 1. The nozzle 10 contains a

generated temperature of the liquid jet onto a fine opening 11; this is usually tubular

Reduced minimum. The increased cohesion of the 15 (length: between about 0.7 mm and 12.7 mm or Liquid jet is achieved without thereby being three to thirty times the diameter) and

the flow velocity or throughput circular in cross section (between about 0.025 mm

of the liquid jet is impaired. and 2.5 mm in diameter). It is located in

The invention is explained in more detail by the drawings of a housing 12 with a rounded one. 20 denotes a passage section 14. The working fluid 17

F i g. 1 a schematic representation of a nozzle enters the opening 11 in order to produce a jet 18

with a cylindrical opening in section and that testify. In the housing 12 for the input section

Associated pressure system for the working fluid, 14 of the nozzle 10 is a thread or another

F i g. 2 is a schematic enlarged illustration of the connection to a high-pressure line 15 at the front in FIG. 1, the very turbulent nozzle which leads to the pressure system 16 for the working fluid flow in the nozzle fluid 17 . Fig. 2 shows the turbulent opening in known devices and the scattering working fluid 19 in the opening of the nozzle and the jet as it emerges from the nozzle . If no long-chain polymer is present in the working fluid 17 is provided. The spread of the

FIG. 3 shows a schematic enlarged illustration 30 of beam 20 is shown in FIGS. 2 and 5. Fig. 3

the in F i g. 1, the nichi turbu- shows the non-turbulent working fluid 21

lent or almost laminar flow of the with one in the opening 11 of the nozzle 10. In the F i g. 3 and 4

long-chain polymer mixed working fluid is the cohesive one that emerges when exiting the nozzle 10

shown in the nozzle and the cohesiveness of the beam 22 generated from the. The when moving the

Nozzle exiting fluid jet is shown, 35 working fluid occurring high shear forces

F i g. 4 shows a cross section through the in FIG. 3 surprisingly have such an effect on the linear

showed liquid jet, with the cohesive liquid polymer at the interface that the friction

is shown, the coefficient at the interface is significantly

5 shows a schematic cross section of the reduced and the polymer reduces the scattering of the generated-scattered liquid jet shown in FIG. 2, where the jet 22 is reduced. The cohesive jet 22 at which the scattering is shown is without significantly reduced velocity

F i g. 6, 8 and 9 graphs generated at.

where the cutting depth against the concentration of the long-chain, natural or synthetic poly-

long-chain polymers in the working fluid or mers are well known and are suitable for

the viscosity of the mixture is shown, and 45 apply in the method according to the invention if they

Fig. 7 is a graph showing that those can be dissolved in the working fluid at concentration against the viscosity of a certain for example by direct dissolution in the working fluid polymer with a low shear gradient of a viscosity with or without the application of heat or meters is shown. by using solvents for the

In the process of the invention, the 50 linear polymers that are with the working fluid are miscible when emitted as a jet of liquid through a nozzle. Suitable long-chain polymers are Working fluid a long-chain polymer in those in which the molecular chains are essentially one Amount admixed that the mixture at borrowed linear and not significantly cross-linked with Smaller shear rate has greater viscosity adjacent molecular chains are, though than the working fluid without polymer. The 55 branches occur in each chain Mixture results when it can be pushed through the nozzle. In general, the preferred ones have long, a liquid jet with larger cohesive chain polymers an average molecular weight ability than when using the working fluid - between 10 * and 7 10 °. Specific examples are alone. The use of long-chain poly-polyalkylene oxides, especially polyethylene oxide, the mers in particular increases the penetration power of the 60 usually in a lower alcohol of 1 to 6 Liquid jet into a processing surface. Carbon atoms, for example isopropanol, dis-

The surprising feature of the invention pergates and in the working fluid, usually

it says that the long-chain, in the working liquid - water, is introduced; alkyl-substituted celluloses,

Dissolved polymer has a small effective viscosity such as methyl cellulose, which is heated in the

at the very large shear rates introduced at 65 working fluid, usually water

Dispensing of the mixture through the nozzle may occur. whereupon the mixture is cooled to the

In the case of small shear gradients, bring the conventional methyl cellulose into solution; and gelatin,

Viscometers occur, the mixture has a properties that are similar to that in the working fluid, usually water

5 Ο 6

solves is. Specifically selected: · - Chosen long chain polymer up to 10,000 ppm polyethylene oxide polymer essential must be soluble in the working fluid, otherwise it is the depth of the cutting action of the working fluid for does not increase the purpose of the present invention by means. In this area a visa was suitable. The characteristics of the working fluid viscosity of the working fluid (small shear determining the choice of long chain polymer. 5 slopes) with a viscometer between a little over 1

As already mentioned, numerous working and 1600-IO " ² poise (Fig. 7) have been determined and it has

known liquids, among which, however, the eco- has shown that the greater viscosities of the

Most common for machining and cutting purposes is the mixture of working fluid and polymer

Water is, this is for the purpose of the present- have been greatly reduced (60 to 90%>) when that's out

preferred the invention. Other fluids, fluid flowing out of the nozzle with the

the ones that have been suggested are different, a viscometer was tested on what was big

Low viscosity, non-chlorinated oils, shear vessels in the nozzle (approx. 10 "see * ¹ ) back-

Add alcohols, glycerin and various mixtures. This linear polymer had the physical

from alcohols and glycerine in the water. All are kaiische property that its measured vis-

due to small viscosities close to the viscosity of the 15 with increasing small shear rates, those

Marked water. The linear polymer in it exposed in the viscometer became smaller

each mixture increases the cohesiveness of the was.

Liquid jet. It has been shown that for that with the polymer

In general, a high-speed displaced water with a nozzle with 0.19 mm through-liquid ^{jet preferably has speeds in the range of the calculated Re:} bi- ~ 2sl ocfficient with a jet range of 170 to 1300 m / sec or more at the outlet. speeds over 150 m / 'sec lower than that for occurs when the nozzle occurs. Usually the speed is water alone and that the speed value of the jet is equal to the speed of sound at which this intersection point lies, for equi-air (330 m see) or more. In order to generate these high-speed pressures with larger nozzle diameters, the working fluid is set below 25 greater and with smaller nozzle diameters less than 700 to 7000 kg / cm * or more. She is. At speeds below the over-snow nozzle usually has a circular crossover point, the coefficients of friction were greater with a diameter between 0.025 and cut than that of water alone.

2.5 mm depending on the particular mixture of The following example II shows the results obtained

Working fluids and linear polymer. The 30 results for the case that the natural polymer

Nozzles can have other cross-sectional shapes with a gelatin dissolved in water as the working fluid

Have surface between 6-10- "and 6 cm 10 ~ ^2." will.

Preferably the nozzle openings (Fig. 1) have Example H.

a rounded entrance section and a "

square exit. 35 The procedure according to Example I was repeated,

There are the working fluid between about where gelatin was used as a linear polymer,

500 and 30,000 parts (especially between 1,000 that was dissolved in water. The pressure on the

and 10,000 parts) of the loose chain polymer per working fluid was 1400 and 1200 kg / cm ² ,

Million parts of the working fluid added. Fer- and a nozzle opening with a diameter of

ner the viscosity of the mixture at small 40 0.24 mm and a length of 6.4 mm was used.

Shear gradients preferably between about 10 and The feed rate was 2 cm / sec below

100 times greater than the viscosity of the working fluid - use a hardwood that is 3.2 mm from the

without long-chain polymer. Nozzle was removed. The results are in the graph

These variables have proven to be particularly useful in the Zuphic representation of FIG. 8 shown from the

in connection with water. 45 shows that the gelatin in a concentration

The general procedure described above gives between 1000 and 30000 ppm the cutting depth in

The measure of the present invention is now increased significantly with hardwood hand.

Specific examples are used to explain what- The viscosity of the gelatin-water mixture

This appeared to be a representative working fluid given the small shear gradient that the

turns. 50 mixture in the viscometer was not exposed to

with increasing shear, as in the case of the

Example «linear polymer of Example I was the case. the

Using the above described before the larger shear gradient occurs in the nozzle

direction with a diameter of 0.19 mm tendc viscosity was much smaller, and the travel

exhibiting and 1.9 mm long nozzle opening and 55 exercise coefficient was also smaller than the coefficient

with a pressure of 2800 kg / cm ² on that as cient for water alone, if the jet speed

Working fluid water was speed greater than about 830 m / sec.

Spruce wood at a conveyor speed has been shown to work well as gelatin

cut right to the beam of 2.2 cm / sec. The linear polymer is suitable. However, it is towards it

Depth of cut was made depending on the concentration, that it is ensured that it is not

Tration of polyethylene oxide "in ppm in water (dis- use is biodegraded. It has also been found

Pergates to about 25 to 35 weight percent in shown that large concentrations of gelatin for

Isopropanol and the water supplied) unier the same, according to Example I by adding

A distance of 3.2 mm and a cutting depth produced at a distance of polyethylene oxide is necessary

Measured 28 mm from the nozzle to which the cutting 65 were.

to determine the effect. The results are shown in the The following example T \ shows that when cutting

graph of Fig. 6 shown. From the obtained result with a modified one

6 it can be seen that the addition of about 500 natural material, namely methyl cellulose.

Example III

The procedure of Example 1 was repeated using methyl cellulose dissolved in water as the working fluid. The working mean pressure was 2950 kg / cm ² . The nozzle was 0.22 mm in diameter and 6.5 mm in length. The conveying speed was 2 cm / sec, and the workpiece surface (Douglas fir) was 3.2 mm away from the nozzle. The results are shown in the graph of FIG. 9, wherein the cutting depth versus viscosity at 10 ~ ² poise the working fluid is applied with a viscometer, which is directly related to the concentration of methyl cellulose in water in the relationship. It has been found that at a viscosity greater than about 2 up to 40 poise (2 percent by weight polymer in water) the depth of cut is increased substantially (2 times). At speeds above 600 m / sec, the coefficient of friction was smaller than that of water, but greater than that for the polymer according to Example I.

It has been found that methyl cellulose is preferred as the long chain polymer because it is easy to use Way can be dissolved directly in water. Furthermore, it is not poisonous, and the viscosities will be not significantly reduced as a result of thinning through the nozzle at high shear rates, so that they can be used again.

The procedure according to Examples I and III was carried out with polyacrylamide and polyethyleneimine as long chain polymers repeated, and these materials were also useful. The viscosities and / odei however, the degradation makes them less suitable than those cited in the above examples Substances. The coefficient of friction for polyethyleneimine was greater than that of water for one Viscosity of 0.6 poise, and the coefficient of friction became excessively large at higher viscosities. Polyacrylamide polymers gave good results,

ίο if the degradation of the polymers as a result of the Passage through the nozzle is not excessively large.

The long chain polymers have been shown to extend the effective life of the nozzle and high pressure pump linings or increase seals. Furthermore, the temperature of the jet is much lower, because the friction in the nozzle is reduced. Therefore, higher working medium pressures can be used, without the jet leaving the nozzle evaporating.

Also, since the concentrations of the long chain polymers are low, the process is economical. as The additional effect of the long-chain polymers was a reduction in the wetting of the workpiece found on the surface and inside.

It has also been shown that when finely divided solids are added to the working medium, the cutting is prevented Hard materials facilitate the erosion of the nozzle by the solids, the long-chain polymers to reduce. Glass beads are particularly suitable. In all cases the solids were in diameter smaller than the nozzle opening.

For this purpose 3 sheets of drawings

«9533/3 (58

Claims (1)

dispensing nozzle in the form of a high-speed liquid patent claims: sigkeitsstrahls is ejected. For this purpose, it is a multitude of different working fluids 1. Process for processing, in particular has been used. From US-PS 2,489,097 and Cutting, a workpiece surface by means of 5 US-PS 3136 649, it is known, for example, any Working fluid, which is in the form of an under-a non-compressible fluid to use. Pressure through a dispensing nozzle with a large flow rate. Water is generally preferred. In speed ejected fine, an increased US-PS 3136649 are also not corro-cohesion having a liquid jet on dying, relatively viscous liquids such as oil, the workpiece surface is sprayed on, as it is liquefied or dissolved in a solvent characterized in that plastics or solvents themselves mentioned as work liquid is a mixture consisting of US Pat. No. 2,985,050 and 2,489,097, it is also 1) Water or has become known to have a low viscosity, to add an abrasive, for example sand, to the working fluid which has a viscosity close to that of water. Ferden non-chlorinated oils, alcohols or ¹ S 5 ^er ψ- ^e ? ^au ^ ^{US "PS 3212378} known from glycerol or from different micro gusagjaat with a gas to mix around the loop to increase of alcohols and glycerol in Wirkungspd of Huss ^ eitsstrahls
Water as a basic liquid component, ^The difficulties with all of the above 2) a viscosity and cohesion of the method then consisting in that the high-liquid jet generated enhancing additive for scattering of a ^30-speed jet tends natural or synthetic long chain upon ejection from the nozzle. The larger the polymer with an essentially linear chain, the pressures exerted on the working fluid and a molecular weight between, the greater the spread produced. This scattering 10 * and 7 · 10 «in an amount of 500 to ^un 8 of ^the high-velocity jet is shown in 30,000 parts per million parts of the basic ^{a5 of a} weak absorption efficiency of the jet, component and, if necessary, of irregular penetration along the 3) an addition required for the dispersion of certain predetermined penetration paths and often results in long-chain polymers that the workpiece surface is made wet in an undesirable manner with alcohols with 1 to 6 carbon atoms. Moisturizing is particularly ^{disadvantageous and possibly 3} ° if absorbent materials are cut. 4) Finely divided solids is used. be ^th. For these reasons, the usage of high-speed liquid jets then 2. The method according to claim 1, characterized ge not so common when the penetration depth, the indicates that the working fluid is a regularity of the cut or the exclusion mixed is used, which as additives a 35 a moistening of the workpiece surface of polyalkylene oxide, in particular a polyethylene are of crucial importance. oxide and an alcohol with 1 to 6 carbon atoms The invention is therefore based on the object contains. the working fluid, especially water, own 3. The method according to claim 1, characterized in lending business through which the cohesion indicates that the working fluid is a gel 40 and the energy density of the high-speed mixing is used, which improves as an additive GeIa liquid jet and the scattering, the contains tine or methyl cellulose. Dissolving or tearing off what is leaving the nozzle Liquid jet is reduced to a minimum. Furthermore, the one in such a ray should 45 by a given pressure in the working stream The temperature generated by the medium must be minimal. Furthermore, in the invention, the improved co- The invention relates to a method for Machining the high-speed liquid jet, in particular cutting, a workpiece surface to be achieved in a simple and economical manner by means of a working fluid, which is in form 50 under pressure through a discharge nozzle without reducing the throughput or the radiation speed is restricted with a high quality value. Furthermore, the speed of the ejected fine liquid jet with increased use of smaller nozzle cross-sections and / or cohesion should be sprayed onto the workpiece surface at lower pressures in the working liquid. By being as it was before.
The method according to the invention is an improved 55 The method according to the invention for processing a high-speed liquid jet with a workpiece surface by means of a work greater cohesion, which has an increased penetration in the form of a penetrating effect under pressure. Dispensing nozzle ejected at high speed The use of a high speed fine, having increased cohesion Liquid jet is sprayed on to penetrate various 60 liquid jets, is thereby ge Workpiece surfaces are known. The high indicates that the working fluid is a mixture • The high-speed liquid jet is particularly useful- consisting of 1. water or a low viscosity bar for cutting, severing, piercing or exhibiting a viscosity close to the viscosity of water rum processing of various workpiece surfaces, non-chlorinated oils, alcohols or glycerine or To get the final shape or design you want 65 different mixtures of alcohols and GIy EU received. In general, a beerin in water is used as the basic liquid ingredient processes in one device knew the working 2. one the viscosity and the cohesion of the fluid liquid pressurized by a jet of absorbency increasing the addition of a natural