The application is for application number is 02229223.3, the applying date is on April 27th, 2002, invention and created name is divided an application for " a kind of machine barrel of conical double-screw plastic extruder " patent application.
Technical background
The machine barrel of conical double-screw plastic extruder all is made up of cylindrical shell and screw rod, and there is following defective in the machine barrel of existing conical double-screw plastic extruder:
1, as Fig. 2, the cylindrical shell 1 of existing technology is an integral body, workpiece is very big (generally long 1850 millimeters, 360 millimeters of diameters), its processing cylindrical shell method is: workpiece slow-speed of revolution rotation, boring bar 6 moving linearlies, car boring endoporus, because boring bar 6 must be less than the size (80 millimeters of diameters) of taper hole small end, so boring bar generally is the slender axles of a diameter below 65 millimeters, when car boring endoporus, its endoporus is because the cutter relieving phenomenon of boring bar, its endoporus bus forms a curved line, so need process endoporus repeatedly, the bus radian in hole could be controlled in the minimum zone.After the boring of workpiece endoporus machines, need grinding, because the poor rigidity of long emery wheel, rotating speed is also low, so grind very slowly, the cutter phenomenon is dug in very easy generation.Because above-mentioned reason, the endoporus of adding workpiece are two crossing cut holes, so 1 process-cycle of cylindrical shell is long, the difficulty of processing height, and also machining accuracy is very low;
2, the gap between two screw rods is less, so on the one hand raw material is enclosed in one by one in the screw channel, form semi-circular, make semi-circular raw material external diameter be heated easily too much, internal diameter can not get effectively being heated, and causes the inequality of being heated, on the other hand, because the gap is too little, make the raw material that flows through the gap be subjected to great shearing force.
3, screw rod has designed a compression section, makes raw material be compressed at this, but because twin-screw is enforceable raw material quantitatively to be carried, and so, when the labor and materials interference, screw rod is impaired easily, and labor and materials are when not enough, and the compression section does not have effect.
Specific embodiments
The utility model embodiment is made up of cylindrical shell 1 and screw rod 2, the endoporus of cylindrical shell 1 is two crossing bellmouths, be respectively equipped with two conical screws 2 in two bellmouths, as shown in Figure 1, cylindrical shell 1 is combined by 6 sections segmentations, cylindrical shell of the present utility model is combined by multistage, so sectional processing cylindrical shell, and is easy to process.
Can see that from Fig. 3 because workpiece is short, so rotating speed can significantly improve, boring bar 6 can be selected for use and differs in size with being fit to taper hole that all size do not wait, so guaranteed favorable rigidity.
Because the endoporus of awl double shell is made up of two crossing taper holes, the center line of two taper hole also has an awl angle, so being divided into any section, cylindrical shell 1 processes the back assembling, be that anyone is out of one's imagine, because the cross section of cylindrical shell 1 is every mutually a little bit poorer, its taper hole size, centre-to-centre spacing all can change.
Processing each section cylindrical shell 1 method is: 1, according to the drawing requirement, process 4 school rods 9 (as Fig. 4,5); 2, will be wherein two be cut into several sections by process cylindrical shell more than 1 sections of needs, as cylindrical shell 1 being divided into 6 sections processing, then school rod 9 also is divided into 6 sections, other two stay standby; When 3, processing the cylindrical shell 1 of any section, at first process a hole, detect the hole taper and the degree of depth with corresponding school rod 9; 4, rotational workpieces is processed another hole, with the size (degree of depth of control school rod) in two holes, the clearance control in claimed range (as Fig. 6) between school, the two holes rod 9; 5, when other all sections of processing, the crack is controlled in the same claimed range between school, the two holes rod 9 of each section; 6, two long school rods 9 are mixed up fixing by the gap that adds man-hour, the barrel jacket with any section gets on then, detects the plan-position up and down of each section, with the method plain grinding plane of match grinding; 7, match grinding is good cylindrical shell links up, and becomes a complete workpiece; 8, two long school rods are cut into correspondent section, perform each size record in detail, match grinding examination criteria during as later batch process by good each section of cylindrical shell of match grinding.With the cylindrical shell 1 that the method processes, endoporus fineness, dimensional accuracy are far superior to all-in-one-piece processing, and its process-cycle shorten dramatically, more crucial is, because the awl double shell is in use, it is very serious to wear and tear as some position, very a certain section cylindrical shell of the replacing of method.
As Fig. 7, be inlaid with carbide chip 4 on the inner hole wall of cylindrical shell 1, carbide chip 4 is embedded in the top of cylindrical shell 1 inner hole wall, because the easiest being worn in top of cylindrical shell 1 inner hole wall.Its processing method is:
1, the cylindrical shell 1 of segmentation is mixed suitable awl mandrel, make it equal in cylindrical shell 1 macropore plane;
2, the circular hole of 10 millimeters of clamping drill diameters that on milling machine, (special tooling arranged), and make the circular hole of 10 millimeters of diameters exceed 2~3 millimeters of machine barrel endoporus;
3, withdraw from the awl mandrel, load onto the carbide alloy pole of 10 millimeters of diameters;
4, the two ends indentation, there of carbide alloy is burnt upward weldering;
5, according to the method for processing any section cylindrical shell 1, proofread and correct the grinding endoporus again, and other technological processes as before.
Like this, under the situation that does not increase great difficulty, improved hardness, in order to deal with regions wear, other nonabradable places maintain the original state.
As Fig. 8,9, the two endoporus intersections on cylindrical shell 1 top have groove 7, the length of groove 7 is 3/5 of cylindrical shell 1 length, have a steam vent 3 above the groove 7, groove 7 is opened at the most rare negative pressuren zone of raw material, and when the raw material of semi-ring is passed in the screw rod rotation, can not take raw material to groove 7 places, so just the steam vent flash can not occur.
The advantage that the two endoporus intersections on cylindrical shell 1 top have groove 7 is:
1, increased the exhaust scope, the gas that can make raw material produce in each process of reaction is effectively discharged, and has increased the serviceability rate of plastic products greatly;
2, can thoroughly eradicate the generation of steam vent flash;
3, owing to solved the exhaust difficulty, and the exhaust scope is big, makes the configuration design aspect of awl twin-screw increase wide space;
4, small-bore steam vent has replaced bigbore steam vent, makes the awl double shell increase area in the utilization of profile.
Screw rod 2 is that quantitatively the length of this section accounts for the 1/2-3/5 of whole screw rod 2 length by the spiral fluted spatial content of discharging opening section, and as Fig. 9, screw rod 2 is a polygon by the cross section of the bar core of charging aperture section.As we can see from the figure, raw material is squeezed at 8 places, zone of screw rod 2 bottoms and adjacent screw rod external diameter, and by loose, simultaneously, raw material moves forward along with the rotation of screw rod with the form of semi-ring again under situation about constantly being stirred all the time at regional 10 places.