Important information concerning catalogue #14
The following information applies to part of our compression spring range CS and CSS, former name SF-TF, SF-TFR, SF-TFX. This does not apply to the series named SS2387, DIN2098 and DIN2098R. The only place with correct numbers at the moment is our at our 3D cad page. For more information, please contact Mårten Glas at Lesjöfors Gas & Stock Springs in Vällingby, +46 8 87 02 50.
Before the launch of catalogue #14 we recalculated the values for R (rate Newton/mm) and Ln (loaded length), since Fn (spring force @ Ln) is calculated as an factor of R and Ln, that value was also changed. Reason for recalculation is based on the fact that material today has G modulus 81 500N/mm². There is only + tolerance on Di/Dm for the affected series and our new calculations was based on the same principal as before, which means that the values was based on the smallest possible diameter. In production you strive to be in the middle of the tolerance range.
It is now decided to present new values for the affected series, the impact various and in the most extreme situation it is up to 25%. In general we will have the following effect:
- Dm will be in the middle of the tolerance range
- R will be lower
- Ln will be higher (shorter stroke)
- Fn will be lower
We will not change the physical dimensions that we use to produce the spring, d, Dm, L0 and Nt will remain the same.
- We need to cancel catalogue #14 since this error will have an impact on new developed articles that is based on incorrect values. This means that we will stop sending out catlogues and refer our customers to our digital catalogues
- We will inform about this in a newsletter and on our homepage
- We will investigate if we can add information on all order confirmation for the affected series
- Our digital catalogues (Catlogue, 3D-Cad and all web shops) will be updated before we inform the market
- We will create new catalogue #14.1 and print in limited edition
- Internal information will be very important, we need to inform customers when discussing items from the affected series. All sales persons needs to understand and be able to explain the situation
- All recalculated springs need name change and we will adjust the mean diameter in the name.
E.g. part 1117 former name CS 0,2X1,2X5 will be changed to CS 0,2X1,32X5 (tolerance for that dimension is +/- 0,12mm)
- We will show 2 diameters for all our compression springs, it will be Dm and Di min (incl –tolerance) for all items in range CS and CSS
- New tolerance table is created (fig 2 next page), before we had 2 tables (A and B), now we have merged them to 1 table. New tolerance table is then based on +/- tolerances for mean diameter
- We aim to have all digital information updated during week 10
- Communcation with the market will be done week 11
- Information if we can add text on order confirmation will come later this week
- Printing cat #14.1 will be earliest Q2 2019 (Obs! Only limited edition will be printed)
- Name change in M3 will be week 11
Fig 1: Difference between Dm and Di min = Dm – Dt – tolerance
e.g. part 3121 Dm:3,05 minus Dt:0,40 minus tolerance:0,15 = Di min:2,50