Factors Affecting Arrow Head Accuracy : Différence entre versions

[version en cours de rédaction][version en cours de rédaction]
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<translate>=Problem=
 
<translate>=Problem=
 
Arrow head setup on a Stuga Sawing centre (not Autoflow) should be simple - the sawing fences centralise around the profile
 
Arrow head setup on a Stuga Sawing centre (not Autoflow) should be simple - the sawing fences centralise around the profile
−
{{Pin|...Autoflow and Microline machines have an axis-driven position for the saw blade centralise position, not a mechanical one}}<br />If the arrow heads are varying or different on one profile to another, there must be other root causes involved - use this checklist to see if
+
{{Pin|...Autoflow and Microline machines have an axis-driven position for the saw blade centralise position, not a mechanical one}}
 +
 
 +
= T Transoms First =
 +
{{Info|..If you can't get T shapes correct,  the you will never get Z profiles correct, so it is important to get reliability and repeatability on simple profiles first}}
 +
 
 +
 
 +
The first important step is to gather reliable test data. Create test pieces 4 off 400mm of narrow, mid and wide T transoms
 +
 
 +
* Carefully check that the bars are symmetrical
 +
* Use a test bar long enough to ensure the offcut is not at the start of the bar 
 +
{{Info|...We want to test the system where the first cut is an arrow head with infeed clamping only. If an offcut is at the start of the bar, it will be clamped on both infeed and outfeed side.}}
 +
* Label them 1, 2 and 3 and 4 as they come off the machine
 +
* Carefully check the dimensions and symmetry of each profile - use the "front to front and back to front method" to check shoulder lengths against each other. This is a quick way to identify discrepancies and compare pieces
 +
* Measure the arrow head location accurately and carefully to get an idea of how the arrow heads perform overall, rather than concentrating on one profile that the operator tells you is wrong.
 +
* If there are any inconsistencies on a profile, repeat the same test - Do you get the same result?
 +
* Test inconsistent profiles again - do you get the same result?
 +
{{Info|...It is important to get consistent inconsistencies to be able to understand what to do about it}}<br />
 
{| class="wikitable"
 
{| class="wikitable"
 
|+Root Cause Table - All Saw, Flowline, ZX3/4/5
 
|+Root Cause Table - All Saw, Flowline, ZX3/4/5
 +
!Symptoms
 
!Potential Root Cause
 
!Potential Root Cause
−
!Symptoms
 
 
!Checks
 
!Checks
 
|-
 
|-
−
|Swarf or offcut stuck stopping the centralise getting to position
+
|No issues found but history of:
−
|All arrow heads out by the same amount on one bar or a set of bars in order, then correct again
 
  
−
Arrow heads out by a long way (>5mm) towards front of machine
+
* All arrow heads out by the same amount on one bar or a set of bars in order, then correct again
  
−
Mitre cut lengths also short (not long)
+
* Arrow heads out by a long way (>5mm) towards front of machine
 +
 
 +
* Mitre cut lengths also short (not long)
 +
|Swarf or offcut stuck was stopping the centralise getting to position
 
|Check the side fence reaches the profile when centralising
 
|Check the side fence reaches the profile when centralising
 
|-
 
|-
−
|Z Support not active for profile
+
|First or last arrow head on bar is different to others
−
Z support incorrectly set for profile rebate
+
|Side fences not parallel
−
|On Z profiles, Bottom arrow head is different to top
+
|[[TM016 Arrow Head Adjustment on Saw#Step 4 - Check Side Fences are Parallel]]
−
First or last arrow head on bar is different to others
 
−
|Check Z support settings
 
−
Manually check how the Z profile is clamped with the Z support out
 
−
|-
 
−
|Profile not symmetrical
 
−
|One profile incorrect but others ok
 
−
|See [[TB0395 How To Test T transom Symmetry]]
 
 
|-
 
|-
 +
|Some profile arrow heads correct, others profiles not. <u>Repeatable results on every test</u>
 
|Arrow head offsets (fiddle factors) historically set
 
|Arrow head offsets (fiddle factors) historically set
−
|Some arrow heads correct, others not, but fixed pattern, not varying along bar length
 
 
|Reset all ofsets to zero before starting
 
|Reset all ofsets to zero before starting
 
|-
 
|-
 +
|First or last arrow head on bar is different to others
 
|Side Clamps not parallel
 
|Side Clamps not parallel
−
|First or last arrow head on bar is different to others
 
 
|Check front fences are parallel with the rear
 
|Check front fences are parallel with the rear
 
|-
 
|-
Ligne 44 : Ligne 55 :
 
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|
 
|
 
|
−
|}
+
|}<br />
 
{| class="wikitable"
 
{| class="wikitable"
 
|+Root Cause Table - SY Drive Only (Refurb Flowlines with SY upgrade, All ZX5s)
 
|+Root Cause Table - SY Drive Only (Refurb Flowlines with SY upgrade, All ZX5s)
 +
!Symptoms
 
!Potential Root Cause
 
!Potential Root Cause
−
!Symptoms
 
 
!Checks
 
!Checks
 
|-
 
|-
−
|SY axis needs lubricating
+
| rowspan="2" |Arrow heads varying with no pattern, changes after redatum
−
|Arrow heads varying with no pattern, change after redatum
 
 
SY axis stalling and has following errors  
 
SY axis stalling and has following errors  
 +
|SY axis needs lubricating
 
|Check SY axis moves full range of movement by hand and via drives screen
 
|Check SY axis moves full range of movement by hand and via drives screen
 
|-
 
|-
 
|SY axis sensor not functioning correctly
 
|SY axis sensor not functioning correctly
−
|Arrow heads varying with no pattern, change after redatum
 
 
|
 
|
 
|-
 
|-
 +
|All arrow heads out by same amount
 
|SY Axis Datum is wrong
 
|SY Axis Datum is wrong
−
|All arrow heads out by same amount
 
 
|Check and double check offsets
 
|Check and double check offsets
−
Check repeatability of SY axis datum visually (mark a line and repeatedly  
+
Check repeatability of SY axis datum visually (mark a line and repeatedly test datuming)
 
{{Warning|..You have to ask yourself why the SY axis datum position has changed - there has to be a root cause. Simply changing the parameter will mask the real problem and therefore guaranteed to return again minutes or days later}}<br />
 
{{Warning|..You have to ask yourself why the SY axis datum position has changed - there has to be a root cause. Simply changing the parameter will mask the real problem and therefore guaranteed to return again minutes or days later}}<br />
−
|}</translate>
+
|}
 +
 
 +
= Z Transoms Second =
 +
Repeat the same tests for Z profiles
 +
<br />
 +
{| class="wikitable"
 +
|+Root Cause Table AFTER T Transoms correct - All Saw, Flowline, ZX3/4/5
 +
!Symptoms
 +
!Potential Root Cause
 +
!Checks
 +
|-
 +
|Bottom arrow head is different to top
 +
First or last arrow head on bar is different to others
 +
|Z Support not active for profile
 +
Z support incorrectly set for profile rebate
 +
|Check Z support settings
 +
Manually check how the Z profile is clamped with the Z support out
 +
|-
 +
|One profile incorrect but others ok
 +
|Profile not symmetrical
 +
|Test Z transom Symmetry (can be difficult!
 +
|-
 +
|Some arrow heads correct, others not, but fixed pattern, not varying along bar length
 +
|Arrow head offsets (fiddle factors) historically set
 +
|Reset all ofsets to zero before starting
 +
|-
 +
|First or last arrow head on bar is different to others
 +
|Side Clamps not parallel
 +
|Check front fences are parallel with the rear
 +
|-
 +
|
 +
|
 +
|
 +
|}
 +
</translate>
 
{{PageLang
 
{{PageLang
 
|Language=en
 
|Language=en

Version du 15 août 2023 à 19:03

Additional root causes that can affect arrow head accuracy

Auteur avatarGareth Green | Dernière modification 17/08/2023 par Gareth Green en cours de rédaction


Additional root causes that can affect arrow head accuracy

Problem

Arrow head setup on a Stuga Sawing centre (not Autoflow) should be simple - the sawing fences centralise around the profile

...Autoflow and Microline machines have an axis-driven position for the saw blade centralise position, not a mechanical one

T Transoms First

..If you can't get T shapes correct, the you will never get Z profiles correct, so it is important to get reliability and repeatability on simple profiles first


The first important step is to gather reliable test data. Create test pieces 4 off 400mm of narrow, mid and wide T transoms

  • Carefully check that the bars are symmetrical
  • Use a test bar long enough to ensure the offcut is not at the start of the bar
...We want to test the system where the first cut is an arrow head with infeed clamping only. If an offcut is at the start of the bar, it will be clamped on both infeed and outfeed side.
  • Label them 1, 2 and 3 and 4 as they come off the machine
  • Carefully check the dimensions and symmetry of each profile - use the "front to front and back to front method" to check shoulder lengths against each other. This is a quick way to identify discrepancies and compare pieces
  • Measure the arrow head location accurately and carefully to get an idea of how the arrow heads perform overall, rather than concentrating on one profile that the operator tells you is wrong.
  • If there are any inconsistencies on a profile, repeat the same test - Do you get the same result?
  • Test inconsistent profiles again - do you get the same result?
...It is important to get consistent inconsistencies to be able to understand what to do about it


Root Cause Table - All Saw, Flowline, ZX3/4/5
Symptoms Potential Root Cause Checks
No issues found but history of:
  • All arrow heads out by the same amount on one bar or a set of bars in order, then correct again
  • Arrow heads out by a long way (>5mm) towards front of machine
  • Mitre cut lengths also short (not long)
 Swarf or offcut stuck was stopping the centralise getting to position Check the side fence reaches the profile when centralising
First or last arrow head on bar is different to others Side fences not parallel TM016 Arrow Head Adjustment on Saw#Step 4 - Check Side Fences are Parallel
Some profile arrow heads correct, others profiles not. Repeatable results on every test Arrow head offsets (fiddle factors) historically set Reset all ofsets to zero before starting
First or last arrow head on bar is different to others Side Clamps not parallel Check front fences are parallel with the rear


Root Cause Table - SY Drive Only (Refurb Flowlines with SY upgrade, All ZX5s)
Symptoms Potential Root Cause Checks
Arrow heads varying with no pattern, changes after redatum

SY axis stalling and has following errors

SY axis needs lubricating Check SY axis moves full range of movement by hand and via drives screen
SY axis sensor not functioning correctly
All arrow heads out by same amount SY Axis Datum is wrong Check and double check offsets

Check repeatability of SY axis datum visually (mark a line and repeatedly test datuming)

..You have to ask yourself why the SY axis datum position has changed - there has to be a root cause. Simply changing the parameter will mask the real problem and therefore guaranteed to return again minutes or days later

Z Transoms Second

Repeat the same tests for Z profiles

Root Cause Table AFTER T Transoms correct - All Saw, Flowline, ZX3/4/5
Symptoms Potential Root Cause Checks
Bottom arrow head is different to top

First or last arrow head on bar is different to others

Z Support not active for profile

Z support incorrectly set for profile rebate

Check Z support settings

Manually check how the Z profile is clamped with the Z support out

One profile incorrect but others ok Profile not symmetrical Test Z transom Symmetry (can be difficult!
Some arrow heads correct, others not, but fixed pattern, not varying along bar length Arrow head offsets (fiddle factors) historically set Reset all ofsets to zero before starting
First or last arrow head on bar is different to others Side Clamps not parallel Check front fences are parallel with the rear

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