AirTAC SI Discontinued: SAI Replacement, Dimensions and Accessories
SI is discontinued. When you order an SI cylinder from our store, we supply the corresponding SAI replacement. Keep your complete SI model as the ordering reference, including the bore, stroke, rod material, magnet, mounting, seal and port-thread options. The supplied cylinder is SAI.
SI and SAI are both ISO 15552 standard-cylinder families, but their mounting details and sensor arrangements need attention during replacement. Matching the bore and stroke alone does not establish that every existing bracket, switch or service part can be reused.
Download the correct catalog
Use the SI catalog to identify the older installation and the SAI catalog to check the cylinder being supplied. For detailed product dimensions and mounting drawings, please download and refer to the PDF catalog.
What stays familiar
The standard single-rod SI and SAI catalogs cover 32, 40, 50, 63, 80, 100, 125, 160 and 200 mm bores. Both describe double-acting operation, adjustable pneumatic cushioning and a general operating pressure range of 0.15–1.0 MPa. The 1.5 MPa proof pressure is a separate test value, not the continuous working-pressure limit.
Match every option in the original order. The rod-material choices include medium-carbon steel, SUS420J2 stainless steel (A) and SUS304 stainless steel (B). The seal options are TPU, fluororubber (H) and NBR (N). The S code identifies a magnetic piston; it does not mean a sensor is included. PT, G and NPT port-thread options must be matched to the selected fittings.
Dimensions: compare the complete mounting drawing
A 40 mm bore provides a useful example. The SI and SAI basic drawings both list A = 159 mm, AC = 105 mm, body dimension B = 53 mm, a 16 mm piston rod and an M12 × 1.25 rod thread. The drawing adds the actual stroke to A and AC. At a 100 mm stroke, those two drawing dimensions are therefore 259 mm and 205 mm.
These are named drawing dimensions, not the overall envelope of a cylinder with all accessories installed. The rear locating boss, mounting hardware, rod-end joint, fittings and sensor must be considered separately.
Even in this example, the mounting-hole depth differs: KA is 16 mm for the historical SI basic arrangement without TC, and 17 mm for SAI. Check the thread, hole depth, bolt engagement and surrounding clearance before reusing fasteners.
| Bore | KA: historical SI without TC → SAI |
|---|---|
| 32 mm | 16 → 16 mm |
| 40, 50 and 63 mm | 16 → 17 mm |
| 80 and 100 mm | 17 → 19 mm |
| 125 mm | 20 → 22 mm |
| 160 and 200 mm | 24 → 30 mm |
The historical SI drawing has separate K and KA entries for cylinders with TC. The comparison above is specifically for SI without TC; use the relevant drawing for a trunnion-mounted installation.
TC trunnions and supports are an important difference
The historical SI catalog specifies a factory-installed TC trunnion with a fixed position. For SAI bores 32–125 mm, the catalog permits position adjustment and separate ordering of the TC mount. SAI 160 and 200 mm TC assemblies remain factory-installed at a fixed position.
The trunnion dimensions also change. For a 32 mm bore, the historical SI TC drawing lists F = 52, G = 50, H = 74 and J = 22 mm. The SAI TC drawing lists F = 68.5, G = 52, H = 76 and J = 31 mm. These letters refer to the TC accessory drawing. They are not the bare-cylinder width and length.
Check the trunnion, TCM1 or TCM2 support, pivot location and machine clearance together. Do not assume that an old SI support assembly will fit simply because the mounting option is still called TC.
Select accessories from the SAI table
Some SAI accessories retain an SI prefix. For example, the SAI32 table lists F-SI32LB foot brackets and F-SI32FA flange mounting. The prefix alone is not a compatibility test.
Other accessory selections differ. For a 32 mm bore, SAI uses F-SE32CA, F-SE32CB and F-SAI32TC. The historical SI table lists F-SI32CA, F-SI32CB and F-SI32TC. Select the complete accessory code for the supplied SAI bore and mounting arrangement, then check its drawing. CR is used with the appropriate CB component; a compatible component is not automatically included with every cylinder order.
For rod-end connections, match the complete metric thread and pitch. Choose an eye, clevis, floating joint or spherical rod-end joint for the required movement and load. A joint does not remove the need to guide the load and avoid transverse force on the piston rod.
Magnetic sensors use a different arrangement
Magnetic SAI cylinders use CMSE and DMSE E-profile sensors fitted into the barrel grooves. The historical SI catalog shows CS1-B/DS1-B and CS1-F/DS1-F/CS1-U/DS1-U arrangements; the latter use the applicable SI fixing seat. Do not carry an old SI fixing seat across to SAI without checking the mounting design.
Select the full sensor model for the required two-wire or three-wire output, NPN or PNP logic, supply voltage, connector and cable length. A quick-connector sensor also needs a correctly matched mating cable. Sensors are separately selected accessories. A non-magnetic cylinder does not become suitable for magnetic position sensing merely by fitting an external switch.
Check the working conditions and supplied weight
Use the SAI limits for the supplied cylinder and the separate ratings of its accessories. The 2022 SAI general operating-temperature range is −20 to 70°C. A fluororubber seal choice does not by itself establish a higher temperature rating for the complete cylinder, sensor, fittings or tubing.
Use the SAI mass reference for the supplied configuration. Catalog mass is a reference, not a measured shipping weight. Rod and seal options, selected mounting hardware, joints, sensors and packaging must be considered when an exact delivered weight is needed. Matching external dimensions does not prove equal SI and SAI mass.
Before fitting the replacement
- Identify the complete original SI model and match its bore, stroke, rod material, magnetic option, mounting, seal and port thread to the supplied SAI configuration.
- Compare the correct basic and accessory drawings, including mounting-hole depth, pivot position, rod thread and clearances in both retracted and extended positions.
- Select mounts, rod-end joints, sensors, mating cables and pneumatic fittings using their complete SAI-compatible codes and connection requirements.
- Isolate the air supply and release stored pressure before replacement. Secure moving loads, align the cylinder and commission the speed and cushioning for the actual application.
This guide covers the standard single-rod SI → SAI replacement. SID, SIJ, SAID and SAIJ are separate configurations and are not included in this replacement statement.
Catalog references: historical SI PDF pages 2–6 (printed pages 24–28); SAI ordering, basic-dimension and accessory pages; and the 2022 AirTAC comprehensive catalog execution section, printed pages 24–25, 33–35, 408–411 and 421. The supply statement above describes fulfillment of SI orders placed with our store.