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Barrels
 
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Spirex Barrels
 Spirex offers you single alloy and bimetallic barrels with a wide range of metallurgical properties. We have the barrel that fits your system and your applications.

Our outstanding alloys include: SPX-60 for general purpose wear; SPX-50 for corrosive wear; and SPX-TITAN for exceptional abrasion resistance.

Single Barrels

SPX-50
It’s one of the most corrosion resistant alloys in the industry. SPX-50 is a nickel/cobalt base alloy with a high chromium content for the most severe corrosive atmospheres.

Applications:
Highly corrosive environments, acidic salts, material with flame retardants, teflon, blowing agent, PVDF.

SPX-60
The standard for bimetallic lining, the SPX-60 is a boron/iron base alloy ideally suited for general purpose wear, particularly for plastics that require good abrasion resistance.

Applications:
Injection and extrusion applications requiring general purpose wear and corrosion resistance. (ABS, acrylics, melamine, nylon, phenolic, polycarbonate, polyesters, PE, PP, PS, PVC, PU, SAN)

SPX-70
This alloy delivers exceptional abrasion and moderate corrosion resistance. It is a composite alloy consisting of a nickel/chromium matrix with a very heavy concentration of high wear carbide particles.

Applications:
Wear resistant and corrosive applications. Any glass-filled/ reinforced compounds, high temperature resins, silicones and multi-purpose machines.


SPX-Titan
The SPX-Titan is the industry’s newest alloy that delivers exceptional abrasion resistance and moderate corrosion resistance. It’s also a composite alloy consisting of a nickel/chromium matrix with a very heavy concentration of high wear tungsten carbide particles. The tungsten carbide and chromium borides with a Rockwell hardness of over 70 provide exceptional wear resistance.

Applications:
Wear resistant and corrosive applications. Any glass filled/reinforced compounds, high temperature resins, silicones and multi-purpose machines.

Bimetallic Alloy Physical Properties
 
SPX-50
SPX-60
SPX-70
SPX-Titan
General Composition
Nickel/Cobalt
Boron/Iron
Ni/Cr/Carbide
Ni/Cr/Tungsten Carbide
Hardness (Rc)
48 - 56
58 - 64
55 - 64
55 - 65
Nominal Tensile Strength (psi)
50,000
50,000
57,000
60,000
Strain to Fracture
0.20%
0.17%
0.20%
0.16%
Density (lb/in3)
0.302
0.273
0.36
0.40

Feed Housings

Spirex can fabricate a feed housing to fit your existing machine or design one to fit your application. Some of the options we can offer are water-cooling, internal grooving, customized hopper mounts or removable liners. If your existing feedthroat is worn out, Spirex can recondition it to new OEM specifications.
 
 

SPI Guidelines for Single Barrels


The following recommendations for single bore barrels for extrusion/injection machinery have been prepared as a guide to manufacturers and processors. These recommendations have been developed over many years and provide working tolerances that produce effective performance with economy of manufacture.


Lengths, Depths & Widths
The following tolerances apply to most linear dimensions of a screw including, but not limited to the overall length of the screw, the flighted surface and the drive. The tolerances increase with the linear dimension involved.

I. Most linear dimensions
English Measurement Metric Measurement
To 12" ± .010" To 300mm ± .25mm
12"-60" ± .030" 300mm-1500mm ± .75mm
60"-120" ± .045" 1500mm-3000mm ± 1.00mm
120"-200" ± .060" 3000mm-5000mm ± 2.25mm
over 200" ± .090" over 5000mm ± 2.25mm

II. Counterbore Depths or Pilot Lengths
English Measurement Metric Measurement
All sizes ± .005" All sizes ± .125mm

Diameters

I. Bores (including counterbores)
English Measurement
To 1˝" dia. (<60" long) + .001" - .000"
1˝"-3" dia. (>60" long) + .002" - .000"
3-5˝" dia. (<120" long) + .002" - .000"
3-5˝" dia. (>120" long) + .0025" - .000"
5˝-8" dia. (<180" long) + .0025" - .000"
5˝-8" dia. (>180" long) + .003" - .000"
8-12˝" dia. (<180" long) + .003" - .000"
8-12˝" dia. (>180" long) + .004" - .000"
Metric Measurement
0-38mm dia. (<1500mm long) + .025mm - .000mm
3-75mm dia. (<1500mm long) + .050mm - .000mm
25-75mm dia. (>1500mm long) + .038mm - .000mm
75-140mm dia. (<3000mm long) + .051mm - .000mm
75-140mm dia. (>3000mm long) + .063mm - .000mm
140-200mm dia. (<4500mm long) + .063mm - .000mm
140-200mm dia. (>4500mm long) + .076mm - .000mm
200-315mm dia. (<4500mm long) + .076mm - .000mm
200-315mm dia. (<4500mm long) + .102mm - .000mm

II. Outside diameters except pilots
English Measurement Metric Measurement
All sizes and lengths ± .005" All sizes and lengths ± .102mm

III. Pilot diameters
English Measurement Metric Measurement
All sizes ± .001" All sizes ± .038mm


Concentricity of Diameters
Concentricity between all inside and outside diameters should be held within .002” TIR or .051mm TIR within one bore diameter of each end. Concentric diameter dimensions further inside of one bore diameter from the ends should be avoided and/or specially tolerated when required.


Straightness
Straightness is generally specified for the bore of the barrel and is measured by TIR.
English Measurement
1-3" bore diameter (<= 24 l/d) .008" TIR
1-3" bore diameter (>= 24 l/d) .010" TIR
3-5˝" bore diameter (<= 24 l/d) .010" TIR
3-5˝" bore diameter (>= 24 l/d) .012" TIR
5˝-8" bore diameter (<= 24 l/d) .012" TIR
5˝-8" bore diameter (>= 24 l/d) .015" TIR
8-12˝" bore diameter (<= 24 l/d) .014" TIR
8-12˝" bore diameter (>= 24 l/d) .016" TIR
Metric Measurement
25-75mm bore diameter (<= 24 l/d) .203mm TIR
25-75mm bore diameter (>= 24 l/d) .254mm TIR
75-140mm bore diameter (<= 24 l/d) .254mm TIR
75-140mm bore diameter (>= 24 l/d) .305mm TIR
140-200mm bore diameter (<= 24 l/d) .305mm TIR
140-200mm bore diameter (>= 24 l/d) .380mm TIR
200-315mm bore diameter (<= 24 l/d) .355mm TIR
200-315mm bore diameter (>= 24 l/d) .406mm TIR

To prevent short "kinks" to which the screw could not conform, any two successive measurements taken less than twice the bore diameter apart should have no more than 1/2 the total allowable TIR.


Bar Test
A second way to check both straightness and bore size is by using a precision ground test bar. This method is detailed in the appendix 1.


Finish
The following surface finishes apply unless specified otherwise.
   
Outer diameters 125 RMS
Counterbores 32 RMS
Pilots 32 RMS
Cylinder bores 8-32 RMS
Feed ports 125 RMS
Vent ports* 32 RMS

*Required within 1/4" of cylinder bore.

The bore shall be free from visual surface defects in the bore over its entire length.


Parallelism & Perpendicularity
Parallel surfaces can be determined by TIR and all dimensions meeting the concentricity recommendations are acceptable.

Perpendicular surfaces to the cylinder bore can be tested by placing the barrel on a surface plate and indicating with an adjustable height table indicator or with a precision square. All mating surfaces should be perpendicular as follows:
  English Measurement Metric Measurement
Pilots and counterbores .0015" TIR .038mm TIR
Flanges .001 TIR per 10" of dia. .038mm TIR per 250mm of dia.


Threads
The variation in threads used is too broad to be addressed in these recommendations. It is suggested that whenever thread selection is possible that either ANSI or ISO standards are adhered to for ease of measurement and compatibility.


Flange Attachments
Barrel flanges may be affixed in accordance with the procedures in Figures 1-6 shown in the appendix depending on the resultant thrust from internal pressure and other design factors. These procedures apply for flanges at either end of the barrel.


Venting
The following warning label should be affixed to a vented extruder or injection barrel supplied without a venting plug.

Warning: This vented injection/extrusion barrel was designed for operation with the vent OPEN ONLY. Operation of this machine with the vent plugged or otherwise closed off may result in serious injury to persons in the vicinity. Check with your supervisor if this vent is intentionally or unintentionally plugged.


Downsizing Injection Barrels
When downsizing (reducing the barrel/screw bore size and resultant shot capacity) an injection molding machine must have the pressure capability reduced or be redesigned for the new resultant pressure. This is necessary to reduce the screw thrust pressure in proportion to the reduction in area of the bore to prevent the barrel from being over pressurized. All units that are downsized should be equipped with a warning label on the barrel where it can be easily seen.


Barrel Construction

Bimetallic Centrifugally Cast and Hot Isostatically Pressed Barrels

The inlay thickness is to be 1/16" (1.6mm) nominal,with a 1/8" (3.2mm) maximum and 1/32" (0.8mm) minimum.

Hardness Standards are those of the manufacturer and are based on the arithmetic means of five hardness measurements taken at random points along the bore. The hardness values vary greatly with the type of inlay. The inlay should have a 100% metallurgical bond at all points determined by ultrasonic techniques.

Nitrided Barrels or Other Single Metal Barrels

Depending on the material used in the outer tube and the bore hardening method, both the hardness and depth of hardness will vary. As a result, the hardness standards are those of the manufacturer.

Sleeved Barrels (New)

All sleeves should be inserted by either shrink fit or press fit with no less than the interference required to maintain the stress levels applying to all barrels detailed in the appendix. In all cases a minimum interference of .001" (.025mm) diametral shrunk per inch of diameter should be used.

Hardness standards are those of the manufacturer and vary with the material and hardening method selected for the sleeve.

Sleeved Barrels (Relined)

The liner material should have a co-efficient of thermal expansion within + 30% of the base (outer tube) material from room temperature through to maximum expected operating temperature.

All internal sleeves should blend to any remaining bore with no visible lip and with no more than the following mismatch in TIR.
English Measurement Metric Measurement
To 2" bore dia. .001" To 50mm bore dia. .025mm
2-3 1/2" bore dia. .002" 50-90mm bore dia. .051mm
> 3 1/2" bore dia. .003" >90mm bore dia. .076mm

In the case of injection barrels, relining of the discharge end should extend a minimum of 2" (50mm) past the maximum backward travel of the rear edge of the check ring on the non-return valve.


Appendix (1)

Barrel/Test-bar/Screw Clearance

Criteria

Clearance specified in the attached two tables are based upon a minimum of .001 inch to a maximum of .0015 inch per inch of diameter between the barrel inside diameter and the screw flight outside diameter. The test-bar outside diameters are sized to the midway point between the screw flight outside diameter and the barrel inside diameter. The lengths of the test-bars specified are based on approximately 15 to 20 times the nominal screw/barrel diameter. All table dimensions are based on the parameters established in the first sentence of this criteria.
English Measurements
Nominal
Diameter		 Specified
Barrel I.D.
Size		 Specified
Diameter
Test Bar		 Specified
Screw
O.D. Size		 Test Bar
Length		 Barrel/
Test Bar
Diametral
Clearance		 Barrel/
Screw
Diametral
Clearance
1-1/8" 1.125 +.001/-.000 1.1235/1.1230 1.1225/1.1220 22" .0015/.003 .0025/.004
1-1/4" 1.250 +.001/-.000 1.2485/1.2480 1.2475/1.2465 24" .0015/.003 .0025/.0045
1-1/2" 1.500 +.001/-.000 1.4985/1.4980 1.497/1.496 26" .0015/.003 .003/.005
1-3/4" 1.750 +.001/-.000 1.7480/1.7475 1.7465/1.7455 30" .002/.0035 .0035/.0055
2" 2.000 +.001/-.000 1.9980/1.9975 1.996/1.995 36" .002/.0035 .004/.005
2-1/4" 2.250 +.001/-.000 2.2480/2.2475 2.246/2.245 38" .002/.0035 .004/.005
2-1/2" 2.500 +.001/-.000 2.4975/2.4970 2.495/2.494 42" .0025/.004 .005/.007
2-3/4" 2.750 +.001/-.000 2.7475/2.7470 2.745/2.744 46" .0025/.004 .005/.007
3" 3.000 +.001/-.000 2.9970/2.9965 2.994/2.993 50" .003/.0045 .006/.008
3-1/4" 3.250 +.002/-.000 3.2465/3.2460 3.2435/3.2425 56" .0035/.006 .0065/.0095
3-1/2" 3.500 +.002/-.000 3.4965/3.4960 3.493/3.492 60" .0035/.006 .007/.010
3-3/4" 3.750 +.002/-.000 3.7465/3.7460 3.743/3.742 62" .0035/.006 .007/.010
4" 4.000 +.002/-.000 3.9960/3.9955 3.992/3.991 68" .004/.0065 .008/.011
4-1/4" 4.250 +.002/-.000 4.2460/4.2455 4.242/4.241 72" .004/.0065 .008/.011
4-1/2" 4.500 +.002/-.000 4.4960/4.4955 4.491/4.490 76" .004/.0065 .009/.012
4-3/4" 4.750 +.002/-.000 4.7455/4.7450 4.741/4.740 82" .0045/.007 .009/.012
5-1/4" 5.250 +.002/-.000 5.2445/5.2440 5.240/5.238 90" .0055/.008 .010/.014
6" 6.000 +.002/-.000 5.994/5.9935 5.988/5.986 96" .006/.0085 .012/.016
8" 8.000 +.002/-.000 7.993/7.992 7.984/7.982 108" .007/.011 .016/.021
 
Metric Measurements
Nominal
Diameter		 Specified
Barrel I.D.
Size		 Specified
Diameter
Test Bar		 Specified
Screw
O.D. Size		 Test Bar
Length		 Barrel/
Test Bar
Diametral
Clearance		 Barrel/
Screw
Diametral
Clearance
30MM 1.181 +.001/-.000 1.1795/1.1790 1.1785/1.1780 22" .0015/.003 .0025/.004
35MM 1.378 +.001/-.000 1.3765/1.3760 1.3750/1.3745 24" .0015/.003 .003/.0045
38MM 1.496 +.001/-.000 1.4945/1.4940 1.493/1.492 26" .0015/.003 .003/.005
40MM 1.575 +.001/-.000 1.5735/1.5730 1.572/1.571 28" .0015/.003 .003/.005
50MM 1.969 +.001/-.000 1.9670/1.9665 1.965/1.964 36" .002/.0035 .004/.005
60MM 2.362 +.001/-.000 2.3595/2.3590 2.357/2.356 38" .0025/.004 .005/.007
65MM 2.559 +.001/-.000 2.5565/2.5560 2.554/2.553 42" .0025/.004 .005/.007
70MM 2.756 +.001/-.000 2.7535/2.7530 2.751/2.750 46" .0025/.004 .005/.07
75MM 2.953 +.001/-.000 2.9500/2.9495 2.947/2.946 50" .003/.0045 .006/.008
80MM 3.150 +.001/-.000 3.1465/3.1460 3.1435/3.1425 56" .0035/.005 .0065/.008
90MM 3.543 +.002/-.000 3.5395/3.5390 3.536/3.535 60" .0035/.006 .007/.010
100MM 3.937 +.002/-.000 3.9330/3.9325 3.929/3.928 68" .004/.0065 .008/.011
105MM 4.134 +.002/-.000 4.1300/4.1295 4.126/4.125 72" .004/.0065 .008/.011
115MM 4.528 +.002/-.000 4.5240/4.5235 4.519/4.518 76" .004/.0065 .009/.012
120MM 4.724 +.002/-.000 4.7195/4.7190 4.715/4.714 82" .0045/.007 .009/.012
135MM 5.315 +.002/-.000 5.3095/5.3090 5.305/5.303 90" .0055/.008 .010/.014
150MM 5.906 +.002/-.000 5.900/5.8995 5.894/5.892 96" .006/.0085 .012/.016