အစားထိုးနိုင်မှုနှင့် စည်းမျဉ်းများ
A customer needs a hose today and the exact fitting is not on the shelf. Some substitutions are routine and some will leak or blow off. This article draws the line: what may be changed, what may never be changed, and what has to be confirmed with the supplier before you commit.
ဖောက်သည်က ယနေ့ လိုအပ်ပြီး အတိအကျ ပစ္စည်း စင်ပေါ် မရှိပါ။ အချို့ အစားထိုးမှုများ လုပ်နိုင်ပြီး အချို့မှာ ယိုစိမ့်ခြင်း၊ ပြုတ်ထွက်ခြင်း ဖြစ်စေပါသည်။ ဤဆောင်းပါးက မျဉ်းကြောင်း ဆွဲပေးပါသည်။
The one rule behind all of this
အခြေခံ စည်းမျဉ်း တစ်ခု
What you may change
ပြောင်း၍ ရသော အရာများ
| Change | Condition | Why it is safe |
|---|---|---|
| Bend angle — straight to 45° or 90° | The route allows it and the port orientation still works | Position 4 only. Thread, seat, bore and hose class are untouched |
| Elbow leg drop — H80 to H100 and so on | There is room for the longer leg | Changes reach, nothing else |
| Hose grade upward — R1 to R2 | The fitting is rated for the hose class and the ferrule matches | More reinforcement than the job needs is not a fault |
| Assembly length | Slack is still allowed for the 4% contraction, and the bend radius is respected | Length is not a compatibility property |
| Supplier | The whole assembly — hose, fitting and ferrule — comes from one maker and is crimped on that maker's die | The combination is qualified, not the individual part |
ကွေးထောင့်၊ ခြေထောက်အရှည်၊ ပိုက်အဆင့် (အထက်သို့)၊ အရှည် — ပြောင်းနိုင်ပါသည်။
What you may never change
ဘယ်တော့မှ မပြောင်းရသော အရာများ
| Never | What happens if you do |
|---|---|
| Sealing face — a 60° cone for a 74° cone, a flat seat for a cone, ORFS for anything else | It screws together and weeps under pressure. The commonest failed substitution we see |
| Thread standard — BSPP for JIS British, BSPT for NPT, DIN for Komatsu | Same or near-same diameters, different pitch or seat. It will start, turn, and then leak |
| Parallel for tapered | A tapered thread in a parallel port seals on nothing |
| Flange pressure class — Code 61 for Code 62 | A Code 62 head will not sit in a Code 61 clamp, and a Code 61 head in a Code 62 port is rated for half the pressure |
| Hose grade downward — R2 to R1 | It will not fail on the bench. It fails weeks later on a loaded machine |
| Ferrule wire count | The crimp diameter is wrong before the machine closes |
| Mixing makers — hose from one, fitting from another, crimped on a third machine | Not an approved assembly. It may blow off under pressure |
| Reusing a crimped fitting, a blown-off fitting, or a hose that has been in service | There is no way to inspect what the first crimp did to the metal |
အဆက်မျက်နှာပြင်၊ သံချည်စံနှုန်း၊ Flange ဖိအားအဆင့်၊ ပိုက်အဆင့် (အောက်သို့)၊ သံကာ သံကြိုးအထပ် — မပြောင်းရပါ။
Pairs that get confused
ရောထွေးတတ်သော အတွဲများ
| These look interchangeable | They are not, because |
|---|---|
| BSPP and JIS British | Same thread, different seat. Check position 3 of the code |
| BSPT and NPT | Both tapered inch threads, similar diameters, different pitch in most sizes |
| JIC and ORFS | Adjacent dash sizes share diameters. JIC is a 74° cone; ORFS is a flat face with an O-ring |
| DIN metric and Komatsu metric | Both M threads. M27×1.5, M30×1.5 and M36×1.5 are Komatsu, not DIN |
| DIN L and DIN S | Some threads appear in both series at different tube sizes. L is medium pressure, S is high |
| Code 61 and Code 62 flanges | Identical bolt pattern, different head diameter |
Substitutions that need the supplier to confirm
Supplier ထံ အတည်ပြုရန် လိုသော အရာများ
A fitting family we have not bought before, even if the code decodes cleanly
Anything in the M27×1.5 size — it matches neither DIN 2353 nor the Komatsu table
Families 014, 710, 879 and 900, where one digit falls outside the published naming rule
Any crimp specification you cannot find in the maker's own table
A fitting intended for a hose grade we do not stock
အထက်ပါ အခြေအနေများတွင် မှန်းဆခြင်းထက် Supplier ထံ မေးပါ။
How to record a substitution
အစားထိုးမှုကို မှတ်တမ်းတင်နည်း
Write what was asked for and what was supplied, both as full specifications, on the job card and on the customer's paperwork. If the assembly is later blamed for a failure, that record is the difference between a warranty conversation and an argument. It also stops the same substitution being repeated by someone who does not know it was a substitution.
တောင်းဆိုသည့် ပစ္စည်းနှင့် ပေးလိုက်သည့် ပစ္စည်း နှစ်ခုလုံးကို Specification အပြည့်အစုံဖြင့် မှတ်တမ်းတင်ပါ။
When to say no
ငြင်းရမည့် အချိန်
When the only available part changes the sealing face, the thread standard or the pressure class, the correct answer is that we do not have it today. A wrong part supplied confidently costs more than a day of waiting — the customer fits it, it leaks, the machine stands, and it comes back with the labour claimed against it.
အဆက်မျက်နှာပြင်၊ သံချည်စံနှုန်း သို့မဟုတ် ဖိအားအဆင့် ပြောင်းသွားမည်ဆိုပါက "ယနေ့ မရှိပါ" ဟု ပြောခြင်းသည် မှန်ကန်သော အဖြေ ဖြစ်ပါသည်။
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