diff --git a/LuaLibs/ProcessFreeContour.lua b/LuaLibs/ProcessFreeContour.lua
index 84d4c94..9650a7c 100644
--- a/LuaLibs/ProcessFreeContour.lua
+++ b/LuaLibs/ProcessFreeContour.lua
@@ -167,6 +167,23 @@ local function VerifyChamfer( Proc, AuxId, nRawId, bMakeVertCham)
    return nChamfer, dDepth, sMilling
 end
 
+---------------------------------------------------------------------
+local function CalcCollisionSafety( vtDir)
+   local dCollSic = 10 * BD.COLL_SIC
+   if abs( vtDir:getX()) > 0.999 or abs( vtDir:getY()) > 0.999 or abs( vtDir:getZ()) > 0.999 then
+      dCollSic = 0
+   elseif abs( vtDir:getX()) > 0.996 or abs( vtDir:getY()) > 0.996 or abs( vtDir:getZ()) > 0.996 then
+      dCollSic = 1 * BD.COLL_SIC
+   elseif abs( vtDir:getX()) > 0.89 or abs( vtDir:getY()) > 0.89 or abs( vtDir:getZ()) > 0.89 then
+      dCollSic = 2.5 * BD.COLL_SIC
+   elseif abs( vtDir:getX()) > 0.866 or abs( vtDir:getY()) > 0.866 or abs( vtDir:getZ()) > 0.866 then
+      dCollSic = 4 * BD.COLL_SIC
+   elseif abs( vtDir:getX()) > 0.707 or abs( vtDir:getY()) > 0.707 or abs( vtDir:getZ()) > 0.707 then
+      dCollSic = 5.5 * BD.COLL_SIC
+   end
+   return dCollSic
+end
+
 ---------------------------------------------------------------------
 local function CalcSpecialAdd( nCrv, bStartVsEnd, dToolDiam)
    -- recupero il dominio della curva
@@ -239,6 +256,8 @@ local function MakeByMill( Proc, nPhase, nRawId, nPartId, dOvmHead)
          dMaxDepth = EgtTdbGetCurrToolMaxDepth() or dMaxDepth
       end
    end
+   local dCollSic = CalcCollisionSafety( vtExtr)
+   dMaxDepth = dMaxDepth - dCollSic
    -- ne verifico la lunghezza per eventuale spezzatura e lavorazione in doppio
    local nStep = 1
    local dStep = 0